Menopausia quirúrgica en pacientes con mutación BRCA, el papel de la terapia hormonal / Surgical Menopause in Patients with BRCA Mutation, the Role of Hormone Therapy

Introducción: las mujeres con mutación BRCA1/2 (mBRCA) tienen un riesgo aumentado de desarrollar cáncer de mama (CM) y ovario (CO). La salpingo-oforectomía bilateral (SOB) se asocia con la reducción del riesgo del 80% para CO y un 50% para CM. Se recomienda realizarla entre los 35 y 40 años. Como consecuencia se produce una menopausia prematura, con un impacto negativo sobre la calidad de vida por la presencia de síntomas climatéricos, aumento del riesgo de enfermedad cardiovascular, osteoporosis y riesgo de alteración cognitiva. La terapia hormonal (THM) es el tratamiento más eficaz para la prevención de estos síntomas. Estado del arte: distintos estudios han demostrado un mayor riesgo de CM en mujeres posmenopáusicas que reciben THM en particular con terapia combinada, estrógeno + progesterona (E+P). Según el metanálisis de Marchetti y cols., en las mujeres portadoras de mBRCA que recibieron THM, no hubo diferencias en el riesgo de CM comparando E solo con E+P. En el estudio de Kotsopoulos, incluso se encontró un posible efecto protector en aquellas que usaron E solo. Otro estudio en portadoras sanas demostró que, en las mujeres menores de 45 años al momento de la SOB, la THM no afectó las tasas de CM. Sin embargo, en las mujeres mayores de 45 años, las tasas de CM fueron más altas. Como el esquema de E+P se asocia con un mayor riesgo relativo (RR) de CM, las dosis de progestágenos utilizados se deberían limitar, eligiendo derivados naturales de progesterona, de uso intermitente para disminuir la exposición sistémica. Según diferentes guías internacionales, a las portadoras de mBRCA sanas que se someten a una SOB se les debe ofrecer THM hasta la edad promedio de la menopausia. Conclusión: la menopausia prematura disminuye la expectativa de vida; es por ello que una de las herramientas para mejorar y prevenir el deterioro de la calidad de vida es la THM. El uso de THM a corto plazo parece seguro para las mujeres portadoras de mBRCA que se someten a una SOB antes de los 45 años, al no contrarrestar la reducción del riesgo de CM obtenida gracias a la cirugía. (AU)

Introduction: women with BRCA1/2 (mBRCA) mutation have an increased risk of developing breast (BC) and ovarian (OC) cancer. Bilateral salpingo-oophorectomy (BSO) is associated with an 80% risk reduction for OC and 50% for BC. The recommended age for this procedure is 35 to 40 years. The consequence is premature menopause, which hurts the quality of life due to the presence of climacteric symptoms, increased risk of cardiovascular disease, osteoporosis, and a higher risk of cognitive impairment. Hormone therapy (MHT) is the most effective treatment for preventing these symptoms. State of the art: different studies have shown an increased risk of BC in postmenopausal women receiving MHT, particularly with combined therapy, estrogen + progesterone (E+P). According to the meta-analysis by Marchetti et al., in women carrying mBRCA who received MHT, there was no difference in the risk of BC compared to E alone with E+P. In the Kostopoulos study, there was also a possible protective effect in those who used E alone. Another study in healthy carriers showed that in women younger than 45 years at the time of BSO, MHT did not affect BC rates. However, in women older than 45 years, BC rates were higher. As the E+P scheme is associated with a higher RR of BC, the doses of progestogens should be limited, choosing natural progesterone byproducts of intermittent use to decrease systemic exposure. According to various international guidelines, healthy mBRCA carriers undergoing BSO should be offered MHT until the average age of menopause. Conclusion: premature menopause decreases life expectancy, which is why one of the tools to improve and prevent deterioration of quality of life is MHT. Short-term use of MHT appears safe for women with mBRCA who undergo BSO before age 45 as it does not counteract the reduction in the risk of MC obtained by surgery. (AU)

Application of next-generation sequencing in detection of BRCA1/2 and homologous recombination repair pathway multi-genes germline mutation and correlation analysis / 中华预防医学杂志

Objective: To investigate the germline mutation status of related genes in breast cancer patients and high-risk individuals by next-generation sequencing. To analyze the correlations between homologous recombination repair (HR) pathway gene mutation status and clinicopathological characteristics of breast cancer patients. To supplement the database of breast cancer related gene mutations in Chinese population. Methods: This study is a cross-sectional study. From October 2020 to September 2021, whole blood samples were collected from 350 breast cancer patients and 49 high-risk individuals, admitted to Peking University People's Hospital and accepted genetic testing voluntarily. Germline mutations in 32 breast cancer related genes were detected by NGS. The clinicopathological characteristics, including age at the onset, family history, unilateral/bilateral tumor, Luminal typing (Luminal A subtype, Luminal B subtype, HER2-enriched subtype and triple negative breast cancer), tumor size and metastasis, were analyzed, and the correlations between HR pathway gene mutation status and clinicopathological characteristics were analyzed by Chi-squared test and Fisher's exact probability test. Results: Among 350 breast cancer patients, 64 (18.3%) cases carried gene pathogenic mutations (including pathogenic and likely pathogenic mutations), including 47 (13.4%) in BRCA1/2, 16 (4.6%) in non-BRCA1/2 genes, 1 (0.3%) in BRCA2 and FANCL. Among 49 high-risk individuals, 7 (14.3%) cases carried gene pathogenic mutations, including 6 (12.3%) in BRCA1/2 and 1 (2%) in ATM genes. BRCA1/2 pathogenic mutations were associated with age at the onset (18%, 8.7%, χ²=6.346, P=0.012), and the BRCA1/2 pathogenic mutation frequency was higher in patients diagnosed at age ≤45 years. HR pathway gene mutations (including pathogenic, likely pathogenic and uncertain significance mutations) were correlated with unilateral/bilateral tumor (49.5%, 68.4%, χ²=4.841, P=0.028) and Luminal typing (45.7%, 62.2%, 32%, 60%, χ²=12.004, P=0.007), and the HR mutation frequencies were higher in patients with bilateral tumor, Luminal B breast cancer and triple negative breast cancer (TNBC). Conclusion: The BRCA1/2 pathogenic mutation frequency in high-risk individuals is similar to that in breast cancer patients, and BRCA1/2 testing is helpful to guide breast cancer screening and prevention in high-risk individuals. Patients with early onset breast cancer, bilateral breast cancer, Luminal B breast cancer and TNBC have higher mutation frequencies of HR pathway genes, and HR pathway genes testing should be conducted as soon as possible to provide laboratory evidence for diagnosis, treatment, prognosis and risk evaluation of breast cancer.

Caracterización epidemiológica del cáncer de mama / Epidemiological characterization of cancer breast

Con el objetivo de realizar la caracterización epidemiológica del cáncer de mama de las pacientes que asisten a la consulta externa de ginecología oncológica en el Instituto Guatemalteco de Seguridad Social (IGSS) de enero a marzo de 2,018, se realizó un estudio descriptivo transversal en 155 pacientes que acudieron a la clínica de mama del Hospital de Gineco Obstetricia del IGSS, con una media de edad de 62 años, el adenocarcinoma ductal infiltrante es el tipo histológico más frecuente en nuestra población tanto en edad reproductiva como en menopausia. Como factor protector el 69% dio lactancia materna. La etapa clínica más comúnmente diagnosticada es IIA. El Luminal A, el más frecuentemente diagnosticado por inmunohistoquímica, seguido del Luminal B y HER2neu. Se diagnostican pacientes mayormente en etapas clínicas tempranas (I y II).

In order to carry out the epidemiological characterization of breast cancer in patients attending the outpatient gynecology oncology consultation at the Guatemalan Social Security Institute (IGSS) from January to March 2018, a descriptive cross-sectional study was carried out in 155 patients who attended the breast clinic of the IGSS Obstetrics Gynecology Hospital, with a mean age of 62 years, infiltrating ductal adenocarcinoma is the most frequent histological type in our population both in reproductive age and in menopause. As a protective factor, 69% breastfed. The most diagnosed clinical stage is IIA. Luminal A, the most frequently diagnosed by immunohistochemistry, followed by Luminal B and HER2neu. Patients are diagnosed mostly in early clinical stages (I and II).

Hormone therapy after risk-reducing surgery in patients with BRCA1/BRCA2 mutation: evaluation of potential benefits and safety

SUMMARY Women with mutations in the BRCA 1 and 2 genes are at increased risk for ovarian and breast cancer and therefore candidates for risk-reducing surgery, including salpingo-oophorectomy and mastectomy. Risk-reducing salpingo-oophorectomy (RRSO) is considered the most effective prophylactic measure for ovarian cancer prevention in this group of patients. This procedure involves loss of ovarian function and induced menopause. Estrogen therapy is the most effective treatment for controlling vasomotor symptoms and improving the quality of life of climacteric women. However, the potential hormonal stimulation of these tumors and the risk of breast cancer are a concern regarding the safety of hormone replacement therapy (HRT) in this population. This article aims to review the current evidence regarding the potential benefits and safety of HRT after RRSO.

RESUMO Mulheres portadoras de mutações nos genes BRCA 1 e 2 possuem risco aumentado para cânceres de ovário e mama e, portanto, são candidatas às cirurgias redutoras de risco, incluindo a salpingo-ooforectomia e a mastectomia. A salpingo-ooforectomia redutora de risco (SORR) é considerada a medida profilática mais efetiva para prevenção do câncer de ovário nesse grupo de pacientes. Esse procedimento implica a perda da função ovariana e menopausa induzida. A estrogenioterapia é o tratamento mais efetivo para o controle de sintomas vasomotores e melhora da qualidade de vida de mulheres no climatério. No entanto, a potencial estimulação hormonal desses tumores e o risco de câncer de mama constituem uma preocupação com a segurança da terapia hormonal (TH) nesta população. Este artigo tem como objetivo uma revisão das evidências atuais quanto aos benefícios potenciais e segurança da TH após SORR.

Expresión tumoral de BRCA1 y resultados clínicos en pacientes uruguayas diagnosticadas de cáncer de mama antes de los 40 años / BRCA1 tumor expression and clinical results in uruguayan patients diagnosed with breast cancer before the age of 40 years old / Expressão tumoral de BRCA1 e resultados clínicos em pacientes uruguaias com diagnóstico de câncer de mama antes dos 40 anos

Resumen: Las mutaciones de BRCA1 son raras en el cáncer de mama (CM) esporádico; sin embargo, su expresión a nivel tumoral se encuentra disminuida o ausente en 30%-50% de los casos. Objetivo: valorar la expresión tumoral de BRCA1 por inmunohistoquímica (IHQ) en mujeres uruguayas diagnosticadas de CM antes de los 40 años. Material y método: se incluyeron pacientes diagnosticadas de CM antes de los 40 años. Se utilizaron los anticuerpos monoclonales anti-BRCA1 MS110 contra el extremo N-terminal y GLK-2 contra el extremo C-terminal. Se calculó la sobrevida global (SVG) y la sobrevida libre de enfermedad (SVLE), para la construcción de las curvas se utilizó el método de Kaplan-Meier y la diferencia de sobrevida se evaluó mediante el test de log rank. Resultados: se incluyeron 40 pacientes, la SVG y la SVLE a cinco años fueron de 73% y 60% respectivamente. La expresión de BRCA1 mediante GLK-2 fue <10% en 16 de las 40 pacientes (40%). La SVG y la SVLE a cinco años para las pacientes con expresión <10% fue de 56% vs 85% para las pacientes con expresión >10% (p=0,015) y de 40% vs 72% (p=0,034) respectivamente. La expresión de BRCA1 mediante MS110 fue <10% en 11 de las 40 pacientes (27,5%). No se encontraron diferencias en la SVG ni en la SVLE a cinco años con este marcador. Conclusión: la pérdida de la expresión tumoral de BRCA1 determinada mediante GLK-2 se encontró en el 40% de las pacientes incluidas y se asoció a una menor SVG y SVLE, por lo que podría tener un valor pronóstico desfavorable en estas pacientes.

Summary: BRCA1 mutations are rare in sporadic breast cancer (CM), however their expression at the tumor level is diminished or absent in 30-50% of cases. Objective: to assess the tumor expression of BRCA1 using immunohistochemistry (IHC) in Uruguayan women diagnosed with BC before the age of 40 years. Material and methods: patients diagnosed with BC before the age of 40 between. The antibodies used were anti BRCA1 MS110 monoclonal antibodies against the N-terminal end and GLK-2 against the C-terminal. Overall survival (OS) and disease free survival (DFS) were calculated; the curves were developed using the Kaplan-Meier method and the difference in survival was evaluated through the log rank test. Results: the average age of the 40 patients included was 36 years. The 5-year OS and DFS were 73% and 60% respectively. The expression of BRCA1 with GLK-2 was <10% in 16 of the 40 patients included (40%). The 5-year OS and DFS for patients with <10% expression was 56% vs. 85% for patients with >10% (p=0.015) and 40% vs. 72% (p = 0.034) respectively. The expression of BRCA1 by MS110 was <10% in 11 of the 40 patients included (27.5%). No differences were found in the 5-year OS or DFS based on the expression of this marker. Conclusion: The loss of BRCA1 expression using GLK-2, which suggests the presence of a truncated protein, was associated with a statistically significantly lower OS and DFS, that the decrease in the BRCA1 protein as determined by GLK2 has an unfavorable prognostic value for young patients with BC.

Resumo: As mutações de BRCA1 são raras no câncer de mama (CM) esporádico; no entanto sua expressão no nível tumoral está diminuída ou ausente em 30-50% dos casos. Objetivo: avaliar a expressão tumoral de BRCA1 por imuno-histoquímica (IHQ) em mulheres uruguaias com diagnóstico de CM antes dos 40 anos. Material e métodos: foram incluídas pacientes com diagnóstico de CM antes dos 40 anos. Foram utilizados anticorpos monoclonais anti BRCA1 MS110 contra o extremo N-terminal e GLK-2 contra o extremo C-terminal. A sobrevida global (SVG) e a sobrevida livre de enfermidade (SVLE) foram calculadas; o método de Kaplan-Meier foi utilizado para a construção das curvas e a diferença de sobrevida foi avaliada usando o teste de log-rank. Resultados: foram incluídas 40 pacientes; a SVG e a SVLE aos 5 anos foram 73% e 60% respectivamente. A expressão de BRCA1 mediante GLK-2 foi <10% em 16 das 40 pacientes (40 %). A SVG e a SVLE aos 5 anos para as pacientes com expressão £10% foi 56% vs. 85% para as pacientes com expressão >10% (p=0,015) e 40% vs. 72% (p=0,034) respectivamente. A expressão de BRCA1 mediante MS110 foi =10% em 11 das 40 pacientes (27,5%). Não foram encontradas diferenças na SVG nem na SVLE aos 5 anos com este marcador. Conclusão: foi encontrada perda da expressão tumoral de BRCA1 determinada por GLK-2 em 40% das pacientes incluídas e foi associada a uma menor SVG e SVLE, o que poderia ter um valor prognóstico desfavorável nestas pacientes.

Detection of a BRCA1 c.2013_2014ins GT variant an ethnic Han Chinese pedigree affected with breast cancer / 中华医学遗传学杂志

OBJECTIVE@#To detect potential variant in an ethical Han Chinese pedigree affected with breast cancer.@*METHODS@#The proband and her relatives were subjected to next-generation sequencing using a target capture sequencing kit containing 121 cancer-related genes. Candidate variants were selected by analysis of their type, frequency in population, and segregation with the phenotype. Candidate variant was verified by Sanger sequencing and TA cloning.@*RESULTS@#A c.2013_2014ins GT variant was detected in the BRCA1 gene among all breast cancer patients from this pedigree but not among healthy females. The variant was not recorded in the 1000 Genome Project database or the Exome Aggregation Consortium (ExAC) database. The frameshifting insertion was predicted to form an premature stop codon in gene transcript and can give rise to a truncated protein.@*CONCLUSION@#The BRCA1 c.2013_2014ins GT variant probably underlies the pathogenesis of breast cancer in this Chinese pedigree.

BRCA1 and BRCA2 mutations in a sample of breast and ovarian cancer families from the Colombian pacific / Mutaciones en los genes BRCA1 y BRCA2 en una muestra de familias con cáncer de mama y/u ovario del pacífico colombiano

Abstract Introduction: Breast cancer is the most common neoplasia of women from all over the world especially women from Colombia. 5%­10% of all cases are caused by hereditary factors, 25% of those cases have mutations in the BRCA1/BRCA2 genes. Objective: The purpose of this study was to identify the mutations associated with the risk of familial breast and/or ovarian cancer in a population of Colombian pacific. Methods: 58 high-risk breast and/or ovarian cancer families and 20 controls were screened for germline mutations in BRCA1 and BRCA2, by Single Strand Conformation Polymorphism (SSCP) and sequencing. Results: Four families (6.9%) were found to carry BRCA1 mutations and eight families (13.8%) had mutations in BRCA2. In BRCA1, we found three Variants of Uncertain Significance (VUS), of which we concluded, using in silico tools, that c.81­12C>G and c.3119G>A (p.Ser1040Asn) are probably deleterious, and c.3083G>A (p.Arg1028His) is probably neutral. In BRCA2, we found three variants of uncertain significance: two were previously described and one novel mutation. Using in silico analysis, we concluded that c.865A>G (p.Asn289Asp) and c.6427T>C (p.Ser2143Pro) are probably deleterious and c.125A>G (p.Tyr42Cys) is probably neutral. Only one of them has previously been reported in Colombia. We also identified 13 polymorphisms (4 in BRCA1 and 9 in BRCA2), two of them are associated with a moderate increase in breast cancer risk (BRCA2 c.1114A>C and c.8755­66T>C). Conclusion: According to our results, the Colombian pacific population presents diverse mutational spectrum for BRCA genes that differs from the findings in other regions in the country.

Resumen Introducción: El cáncer de mama es la neoplasia más común en mujeres de todo el mundo, y, también de Colombia. 5% a 10% de todos los casos son causados por factores hereditarios; 25% de estos casos tienen mutaciones en los genes BRCA1/BRCA2. Objetivo: El propósito de este estudio fue el de identificar mutaciones asociadas con riesgo de cáncer de mama y/u ovario familiar en pacientes del pacífico colombiano. Métodos: Fueron revisados para mutaciones en BRCA1 y BRCA2 de línea germinal mediante SSCP y secuenciación 58 familias de alto riesgo para cáncer de mama y/u ovario y 20 controles Resultados: cuatro familias (6.9%) presentaron mutaciones en BRCA1 y ocho familias (13.8%) en BRCA2. En BRCA1, encontramos tres variantes de significado clínico desconocido (VUS), de las cuales concluimos, usando herramientas bioinformáticas, que c.81­12C>G y c.3119G>A (p.Ser1040Asn) son probablemente deletéreas, y c.3083G>A (p.Arg1028His) es probablemente neutral. En BRCA2, encontramos tres VUS: una mutación nueva y dos previamente descritas, usando análisis bioinformáticos, concluimos que c.865A>G (p.Asn289Asp) y c.6427T>C (p.Ser2143Pro) son probablemente deletéreas y c.125A>G (p.Tyr42Cys) es probablemente neutral. Solo una de ellas ha sido reportada previamente en Colombia. También identificamos 13 polimorfismos (4 en BRCA1 y 9 en BRCA2), dos de ellos asociados con un moderado incremento del riesgo para cáncer de mama (BRCA2 c.1114A>C and c.8755­66T>C). Conclusión: de acuerdo con nuestros resultados, la población del suroccidente colombiano presenta un espectro mutacional diverso para los genes BRCA que difiere de lo encontrado en otras regiones del país.

Investigação da dinâmica mutacional em tumores triplo-negativos da mama através do sequenciamento de DNA tumoral circulante / Investigation of mutational dynamics in triple-negative breast cancer through circulating tumor DNA sequencing

O câncer de mama de imunofenótipo triplo-negativo (TN) é considerado um subtipo agressivo correspondendo a 10-20% dos casos. É caracterizado pela ausência dos receptores hormonais de estrogênio (ER) e de progesterona (PR) além de não apresentar super-expressão/amplificação do receptor 2 do fator de crescimento epidérmico humano (HER2). Sendo assim, as terapias hormonais e moleculares efetivas em outros subtipos de câncer de mama, não têm efeito nesses tumores. A quimioterapia sistêmica neoadjuvante é o tratamento mais utilizado nesse subtipo de tumor de mama, sendo que para as pacientes que obtêm resposta patológica completa (RPC) observa-se um excelente prognóstico, entretanto no subgrupo com neoplasia residual observa-se prognóstico ruim. Isso ilustra a heterogeneidade clínica do tumor TN, com um subgrupo de tumores significativamente sensíveis à quimioterapia e outro resistente. Perda de função no gene BRCA1 tem sido frequentemente reportada em tumores TN de mama, seja por mecanismos genéticos ou epigenéticos. Há evidências de que tumores com deficiência de BRCA1 apresentam boas respostas a determinadas modalidades terapêuticas, como por exemplo, sais de platina e inibidores de PARP. Assim, a investigação mais detalhada no mecanismo de resposta ao tratamento, em mulheres acometidas com tumores TN, no contexto de deficiência de BRCA1, é de grande importância. A detecção de DNA tumoral circulante (ctDNA) tem surgido como uma estratégia pouco invasiva capaz de refletir as mutações presentes nas neoplasias, permitindo um acompanhamento do comportamento tumoral ao longo do tempo com promissor valor preditivo e prognóstico. Dessa forma, esse projeto objetivou investigar a dinâmica mutacional durante o tratamento quimioterápico, antes e após a cirurgia, através da análise de DNA tumoral circulante (ctDNA) como biópsia líquida em plasma de pacientes com tumores TN classificados em hereditários e esporádicos. Investigamos de forma ampla as características genéticas dos tumores TN e das pacientes em associação com as características clínicas e de resposta a tratamento. Quarenta e três pacientes com tumores TN foram recrutadas para o estudo e submetidas a teste genético para avaliar mutações germinativas patogênicas em genes de predisposição a câncer de mama. Com isso, classificamos 21% dos tumores em hereditários e 79% em esporádicos, onde 7 (16,3%) foram de pacientes portadoras de mutações germinativas em BRCA1, uma (2,3%) em BRCA2, uma (2,3%) em TP53. Além disso, 25 foram portadoras de variantes de significado incerto (58,1%) e 9 (20,9%) casos foram negativos. Desse total, 34 pacientes já foram avaliadas quanto à resposta ao tratamento neoadjuvante, sendo que 18 (53%) pacientes apresentaram doença residual e 16 (47%) evoluíram com RPC. A investigação do tecido tumoral foi possível para 23 casos. Desses, 3 tumores (13%) foram classificados com alta carga mutacional. Ainda, para 18 tumores foi possível identificar variantes somáticas nos painéis utilizados com uma média de 2 variantes/tumor. O gene mais frequentemente mutado foi o TP53 (65%) seguido de SYNE1 (16,7%) e outros menos frequentes. Não houve associação entre genes preferencialmente mutados e a classificação dos tumores em hereditários ou esporádicos. Para 17 das 18 pacientes com mutações somáticas detectadas no tumor foi realizada a investigação no DNA circulante no plasma antes do início do tratamento (baseline). Um total de 10 pacientes (58,8%) foi positivo para ctDNA. Observou-se uma tendência de maiores níveis de ctDNA nos casos que evoluíram com doença residual em relação aos que obtiveram resposta patológica completa, sugerindo uma associação entre a quantidade de DNA tumoral e ctDNA. Durante o monitoramento, foi observada que para 7 (41%) casos houve persistência de ctDNA, a qual antecipou achados clínicos como, progressão local e metástase. Nesse trabalho, reforça-se a associação entre inativação de BRCA1 e os tumores TN e é demonstrado o potencial do monitoramento de ctDNA em amostras de plasma para antecipar progressão da doença mostrando uma ferramenta de grande potencial para monitoramento de pacientes submetidos à quimioterapia

Triple-negative breast cancer (TNBC) is considered an aggressive breast cancer subtype corresponding to 10-20% of cases. It is characterized by the absence of estrogen (ER) and progesterone (PR) hormonal receptors and lack of overexpression/amplification of the human epidermal growth factor receptor 2 (HER2). Thus, hormonal and molecular therapies effective in other breast cancer subtypes have no effect on these tumors. Neoadjuvant systemic chemotherapy is the most widely used treatment for TNBC, and patients with pathological complete response (pCR) have an excellent prognosis, whereas in the subgroup with residual disease, a poor prognosis is observed. This illustrates the clinical heterogeneity of TNBC, with one subset of tumors being sensitive to chemotherapy and one resistant. Loss of function in the BRCA1 gene has often been reported in TNBC, either by genetic or epigenetic mechanisms. There is evidence that BRCA1-deficient tumors have good responses to certain therapeutic modalities, such as platinum salts and PARP inhibitors. Thus, a more detailed investigation of the mechanism of response to treatment in women with TNBC in the context of BRCA1 deficiency is of great importance. The detection of circulating tumor DNA (ctDNA) has emerged as a noninvasive strategy capable of reflecting the mutations present in the neoplasms, allowing the monitoring of tumor behavior over time with promising predictive and prognostic value. Thus, this project aimed to investigate the mutational dynamics during chemotherapy treatment, before and after surgery, through the analysis of ctDNA as a liquid biopsy in plasma of patients with hereditary and sporadic TNBC. We have broadly investigated the genetic characteristics of TNBC and patients in association with clinical and treatment response characteristics. Forty-three patients with TNBC were recruited to the study and underwent genetic testing to evaluate pathogenic germline mutations in breast cancer predisposing genes. We classified 21% of tumors as hereditary and 79% as sporadic, where 7 (16.3%) were from patients with germline mutations in BRCA1, one (2.3%) in BRCA2 and one (2.3%) in TP53. In addition, 25 (58.1%) had variants of uncertain significance and 9 (20.9%) cases were negative. Of this total, 34 patients have already been evaluated for response to neoadjuvant treatment, and 18 (53%) patients had residual disease and 16 (47%) evolved with pCR. Investigation of tumor tissue was possible for 23 cases. Of these, 3 tumors (13%) were classified with high mutational load. Furthermore, for 18 tumors it was possible to identify somatic variants in the panels used with an average of 2 variants per tumor. The most frequently mutated gene was TP53 (65%) followed by SYNE1 (16.7%) and other less frequent genes. There was no association between preferentially mutated genes and tumor classification in hereditary or sporadic. For 17 of the 18 patients with somatic mutations detected in the tumor, circulating plasma DNA was investigated before treatment (baseline). A total of 10 patients (58.8%) were positive for ctDNA. There was a trend for higher levels of ctDNA in cases that evolved with residual disease than in those with pCR, suggesting an association between the amount of tumor DNA and ctDNA. During the monitoring, it was observed that 7 (41%) cases were persistent for ctDNA, which anticipated clinical findings such as local progression and metastasis. In this study, the association between BRCA1 inactivation and TNBC is reinforced and it is demonstrated the potential of monitoring ctDNA in plasma samples for the anticipation in the identification of disease progression, providing a tool of great potential for monitoring residual disease in patients undergoing chemotherapy

Clinical significance of variants of unknown significances in BRCA genes / 부인종양

No abstract available.

Novel Germline Mutations of BRCA1 and BRCA2 in Korean Familial Breast Cancer Patients / 전남의대학술지

Breast cancer is the second most common cancer in Korean women. Germline mutations in the BRCA1 and BRCA2 genes cause hereditary breast cancer and are detected in 15–20% of hereditary breast cancer. We investigated the BRCA1 and BRCA2 mutations in 114 familial breast cancer patients using next-generation sequencing. We confirmed 20 different mutations of BRCA1 and BRCA2 in 25 subjects (21.9%). Two such mutations in eight patients were novel (not reported in any variant database or previous study). Six mutations have been reported as disease-causing mutations in public databases. Seven mutations were found only in a single nucleotide polymorphism database and one mutation has been reported in Korea. The BRCA1/2 mutation frequency was similar to that of other studies on familial breast cancer patients in the Korean population. Further studies should examine more cases and mutations of whole exons.

Carcinoma de ovario en paciente con mutación del gen BRCA1. Diagnóstico tras biopsia de adenopatía cervical, en el contexto de un síndrome paraneoplásico cutáneo / Ovarian carcinoma in a patient with a BRCA1 gene mutation. Diagnosis after biopsy of cervical adenopathy, in the context of a cutaneous paraneoplastic syndrome

RESUMEN El cáncer epitelial de ovario representa uno de los tumores ginecológicos más letales ya que más del 75% de las pacientes son diagnosticadas en estadío avanzado. Aún no se ha demostrado que la realización de pruebas y exámenes pélvicos rutinarios haya reducido la mortalidad, no existiendo actualmente, un cribado eficaz para su diagnóstico precoz. Aunque la sintomatología metastásica extraperitoneal más común es el derrame pleural, las linfadenopatías neoplásicas a nivel supraclavicular aparecen hasta en el 4% de casos, generalmente asociándose a un mal pronóstico. La identificación de una adenopatía supraclavicular se relaciona hasta en un 58-83% de los casos, con el hallazgo de una tumoración maligna. Por otro lado, la dermatomiositis del adulto puede tener un origen paraneoplásico en un 15-25% de las ocasiones, siendo el cáncer de mama y de ovario la etiología más frecuente en la población femenina. Las pacientes portadoras de mutaciones en los genes BRCA 1 y 2 tienen un aumento del riesgo de padecer neoplasias de mama y ovario. En aquellas afectas de un cáncer de ovario y portadoras de una mutación en los genes BRCA, no se debería plantear una cirugía profiláctica de rutina sobre la mama, al menos en los primeros 5 años tras el diagnóstico de la neoplasia ovárica. Presentamos el caso de una paciente portadora de una mutación germinal del gen BRCA 1, que debuta con un cáncer de ovario, tras el estudio de una adenopatía neoplásica de cuello, biopsiada en el contexto de un síndrome paraneoplásico cutáneo.

ABSTRACT Epithelial ovarian cancer represents one of the most lethal gynecological tumors, since more than 75% of affected women are diagnosed at an advanced stage. However, studies have not demonstrated yet that performing routine pelvic exams and tests had reduced mortality in ovarian cancer, and currently there is no effective screening for early diagnosis. The most common extraperitoneal metastatic symptomatology of ovarian cancer is pleural effusion, but there are other, like neoplastic lymphadenopathies at supraclavicular level, described in up to 4% of cases and generally related to a poor prognosis. The identification of a supraclavicular adenopathy is associated with the finding of a malignant tumor in 58-83% of the cases. On the other hand, adult dermatomyositis can have a paraneoplastic origin in 15-25% of patients, being breast and ovarian cancer the most frequent etiology in the female population. Patients with BRCA 1 and 2 genes mutations have an increased risk of breast and ovarian malignancies. In those affected by an ovarian cancer and carriers of a mutation in the BRCA genes, routine prophylactic surgery should not be considered on the breast, at least in the first 5 years after the diagnosis of ovarian neoplasia. We present the case of a patient with a germinal mutation of the BRCA 1 gene, who debuts with an ovarian cancer, after the study of a neoplastic adenopathy of neck, biopsied in the context of a cutaneous paraneoplastic syndrome.

Mastectomía profiláctica versus vigilancia en la prevención de cáncer de mama en mujeres BRCA positivo / Prophylactic mastectomy versus surveillance for the prevention of breast cancer in women's BRCA carriers

INTRODUCCIÓN: Las mujeres que poseen mutaciones en genes BRCA tienen un alto riesgo de desarrollar cáncer de mama. Por lo anterior, se han planteado múltiples estrategias preventivas dentro de las cuales se encuentra la mastectomía profiláctica. Existe controversia sobre si los beneficios de esta intervención superan al de una vigilancia activa, en especial considerando el impacto físico y psicológico asociado. MÉTODOS: Para responder esta pregunta utilizamos Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud, la cual es mantenida mediante búsquedas en múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, analizamos los datos de los estudios primarios, realizamos un metanálisis y preparamos una tabla de resumen de los resultados utilizando el método GRADE. RESULTADOS Y CONCLUSIONES: Identificamos 13 revisiones sistemáticas que en conjunto incluyen 50 estudios primarios. Concluímos que si bien la mastectomía profiláctica se asocia a efectos adversos frecuentes, reduce la incidencia de cáncer de mama y la mortalidad, y podría asociarse a altos niveles de satisfacción.

INTRODUCTION: Women who have mutations in BRCA genes have a high risk of developing breast cancer. Therefore, multiple preventive strategies have been proposed, within which is prophylactic mastectomy. Considering physical and psychological effects of surgery, the controversy is established as to whether the preventive effect exceeds that of active vigilance. METHODS: To answer this question we used Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach. RESULTS AND CONCLUSIONS: We identified 13 systematic reviews including 50 studies overall. We concluded prophylactic mastectomy is associated with frequent adverse effects, but probably reduces the incidence of breast cancer and decreases mortality, in addition to being associated with high levels of satisfaction.

Mutational spectrum in breast cancer associated BRCA1 and BRCA2 genes in Colombia / Espectro de mutaciones en los genes BRCA1 y BRCA2 asociados a cáncer de mama en Colombia

Abstract Introduction: The risk of developing breast and ovarian cancer is higher in families that carry mutations in BRCA1 or BRCA2 genes, and timely mutation detection is critical. Objective: To identify the presence of mutations in the Colombian population and evaluate two testing strategies. Methods: From a total universe of 853 individual blood samples referred for BRCA1 and BRCA2 typing, 256 cases were analyzed by complete direct sequencing of both genes in Myriad Genetics, and the remaining 597 cases were studied by partial sequencing based on founder mutations in a PCR test designed by ourselves ("Profile Colombia"). Results: We found 107 patients carrying deleterious mutations in this group of patients, 69 (64.5%) located in BRCA1, and 38 (35.5%) in BRCA2. Overall, we detected 39 previously unreported mutations in Colombia (22 in BRCA1 and 17 in BRCA2) and only 4 out of the 6 previously reported founder mutations. Sixty four out of 597 patients (10.7%) studied by "Profile Colombia" showed mutations in BRCA1 or BRCA2, and 41/256 patients (16%) showed mutations by complete BRCA1-BRCA2 sequencing. Conclusions: The spectrum of 44 different mutations in Colombia as detected in our study is broader than the one previously reported for this country. "Profile Colombia" is a useful screening test to establish both founder and new mutations (detection rate of 10.7%) in cases with family history of breast cancer. Complete sequencing shows a detection rate of 16.0%, and should complement the study of the genetic basis of this disease.

Resumen Introducción: El riesgo de desarrollar cáncer de mama y cáncer de ovario puede transmitirse en familias que porten mutaciones en los genes BRCA1 o BRCA2. La detección de estas mutaciones permite tomar decisiones oportunas en el ámbito de la medicina preventiva. Objetivo: Estudiar el espectro de mutaciones en la población colombiana y evaluar dos estrategias de detección. Metodos: Se incluyeron en total 853 pacientes con diagnóstico de cáncer de mama y con solicitud de análisis de los genes BRCA1 y BRCA2. Un total de 256 pruebas se analizaron mediante secuencia directa completa de estos genes en Myriad Genetics, y las restantes 597 se estudiaron mediante secuencia parcial basada en mutaciones fundadoras a través de la prueba "Perfil Colombia", implementada por nosotros. Resultados: Se detectaron 107 pacientes portadores de mutaciones en pacientes colombianos, 69 de las cuales estaban localizadas en BRCA1 y 38 en BRCA2. De estas 39 mutaciones son nuevas (22 en BRCA1 y 17 en BRCA2) y solo se hallaron 4 de las 6 mutaciones reportadas previamente como fundadoras en Colombia. En 64/597 pacientes analizados mediante el "Perfil Colombia" se detectaron mutaciones en BRCA1 o BRCA2, así como en 41/256 pacientes que solicitaron la secuenciación completa de los genes BRCA1 y BRCA2. Conclusiones: El espectro de mutaciones fundadoras en Colombia es más amplio que el reportado anteriormente para este país. El "Perfil Colombia" es una prueba que revela a la vez mutaciones fundadoras y mutaciones nuevas, con una tasa de detección del 10.7%. La secuenciación completa presenta una tasa de detección del 16.0% y puede complementar el diagnóstico de la base genética de esta enfermedad.

Clinically Significant Unclassified Variants in BRCA1 and BRCA2 genes among Korean Breast Cancer Patients / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Unclassified variants (UVs) of BRCA1 and BRCA2 genes are not defined as pathogenic for breast cancer, and their clinical significance currently remains undefined. Therefore, this study was conducted to identify potentially pathogenic UVs by comparing their prevalence between breast cancer patients and controls. MATERIALS AND METHODS: A total of 328 breast cancer patients underwent BRCA1/2 genetic screening at the National Cancer Center of Korea. Genetic variants of BRCA genes that were categorized as unclassified according to the Breast Cancer Information Core database were selected based on allelic frequency, after which candidate variants were genotyped in 421 healthy controls. We also examined family members of the study participants. Finally, the effects of amino acid substitutions on protein structure and function were predicted in silico. RESULTS: Genetic tests revealed 33 UVs in BRCA1 and 47 in BRCA2. Among 15 candidates genotyped in healthy controls, c.5339T>C in BRCA1 and c.6029T>G, c.7522G>A in BRCA2 were not detected. Moreover, the c.5339T>C variant in the BRCA1 gene was detected in four patients with a family history of breast cancer. This nonsynonymous variant (Leu1780Pro) in the BRCA1 C-terminal domain was predicted to have an effect on BRCA1 protein structure/function. CONCLUSION: This study showed that comparison of genotype frequency between cases and controls could help identify UVs of BRCA genes that are potentially pathogenic. Moreover, ourfindings suggest that c.5339T>C in BRCA1 might be a pathogenic variant for patients and their families.

A Novel Germline Mutation in BRCA1 Causes Exon 20 Skipping in a Korean Family with a History of Breast Cancer / 한국유방암학회지

Germline mutations in the BRCA1 and BRCA2 genes are strong genetic factors for predispositions to breast, ovarian, and other related cancers. This report describes a family with a history of breast and ovarian cancers that harbored a novel BRCA1 germline mutation. A single nucleotide deletion in intron 20, namely c.5332+4delA, was detected in a 43-year-old patient with breast cancer. This mutation led to the skipping of exon 20, which in turn resulted in the production of a truncated BRCA1 protein that was 1773 amino acids in length. The mother of the proband had died due to ovarian cancer and had harbored the same germline mutation. Ectopically expressed mutant BRCA1 protein interacted with the BARD1 protein, but showed a reduced transcriptional function, as demonstrated by the expression of cyclin B1. This novel germline mutation in the BRCA1 gene caused familial breast and ovarian cancers.

Expresión de BRCA1 en lesiones benignas y malignas de la mama / BRCA1 expression in benign and malignant breast lesions

La mayor parte de los carcinomas de mama son cánceres esporádicos; sin embargo, existe una proporción, estimada entre el 5 y el 10%, en la cual aparece una predisposición hereditaria al cáncer, asociado principalmente a mutaciones germinales en los genes BRCA1 y BRCA2; tales mutaciones incrementan la predisposición para el desarrollo de la enfermedad durante el transcurso de la vida. El objetivo general de este trabajo fue valorar la expresión del gen BRCA1 por inmunohistoquímica (IHQ). El estudio se realizó en mujeres diagnosticadas con lesiones benignas o con carcinoma ductal infiltrante de mama en seguimiento en el Instituto de Oncología “Dr. Miguel Pérez Carreño” de Valencia, Venezuela. Se analizó la expresión de la proteína BRCA1 y los resultados obtenidos se compararon con la clasificación de las lesiones benignas propuesta por Dupont y Page y los subtipos moleculares intrínsecos definidos por IHQ. De este análisis se obtuvo que tanto en las lesiones no infiltrantes (proliferativas y carcinoma in situ), así como en los carcinomas infiltrantes, predominaron los casos con un marcaje nuclear de BRCA1 por IHQ ≤10%. Además, la relación de la expresión de BRCA1 con la media de la supervivencia global, obtuvo valor pronóstico desfavorable, cuando la expresión nuclear y citoplasmática de BRCA1 fue ≤10%, con p<0,05. Finalmente, en base a los resultados, se sugiere que en el algoritmo de abordaje de mujeres con riesgo de padecer cáncer de mama, se incluya la valoración de la expresión de BRCA1 por IHQ.

The majority of breast cancers are sporadic cancers; however, there is an estima¬ted proportion of 5% to 10%, where a hereditary predisposition appears, mainly associated with germline mutations in the BRCA1 and BRCA2 genes. Such mutations increase the predis-position to develop the disease during the course of life. The overall objective of this work was to evaluate the expression of the BRCA1 gene by immunohistochemistry (IHC). The study was conducted in women diagnosed with benign lesions or invasive breast ductal carcinoma in follow-up care at the Institute of Oncology “Dr. Miguel Perez Carreño” in Valencia, Venezuela. Expression of the BRCA1 protein was analyzed and the results were compared with the benign lesions classification given by DuPont and Page and the intrinsic molecular subtypes defined by IHC. From this analysis it was found that in both, non-infiltrative lesions (proliferative and carcinoma in situ), as well as in infiltrating carcinomas, predominated the cases with BRCA1 nuclear labeling by IHC (≤10 %). Furthermore, the relationship of expression of BRCA1 with the average overall survival, showed a poor prognostic value obtained when the nuclear and cytoplasmic expression of BRCA1 was ≤10%, with p<0.05. Finally, based on the results, it is suggested that the assessment of BRCA1 expression by IHC should be included in the approach algorithm of women at risk of developing breast cancer.

Knowledge and willingness of breast cancer patients from Shanghai for genetic counseling and gene testing / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the knowledge and willingness of breast cancers patients from Shanghai for genetic counseling and gene testing.</p><p><b>METHODS</b>A total of 428 patients filled out the questionnaire and the data was statistically analyzed.</p><p><b>RESULTS</b>Most of the patients were unaware of genetic counseling and gene testing. But after a brief introduction, a majority of them were willing to accept genetic counseling and recommend their family members to participate. The willingness was education- and age-related. When told that gene testing may benefit themselves, 92.1% of the patients were willing to be tested. However, when told that gene testing may only benefit their family, only 33.9% of the patients were willing to join the testing. The acceptance was also age-, education- and family income-related. The difference was statistically significant. Moreover, the willingness ratio to participate the gene testing was lower than expected. Overall, 74.1% of the patients were willing to accept cheaper preliminary gene screening, whilst only 19.2% were willing to accept genetic testing of higher price. Despite of being told that testing results will be maintained as confidential, still 43.2% worried about adverse effects. Such patients tended to younger, from low-income families, with a family history of associated cancers, or personal history of other cancers. The difference was statistically significant.</p><p><b>CONCLUSION</b>The majorities of patients do not know but are willing to accept genetic counseling and gene testing and recommend their family to participate. Lack of genetic knowledge, cost for the testing and concerns about discrimination are the obstacles for patients to participate in genetic counseling and gene testing. To spread the knowledge about breast cancer and establish a follow-up screening system for high-risk population may improve the tertiary prevention for breast cancer.</p>

Comparison of Targeted Next-Generation and Sanger Sequencing for the BRCA1 and BRCA2 Mutation Screening

No abstract available.

Assessment of adherence to the guidelines for the management of nausea and vomiting induced by chemotherapy / Avaliação da aderência à diretriz de cuidados para náuseas e vômitos induzidos por quimioterapia

ABSTRACT Objective: To assess adherence of the prescribing physicians in a private cancer care center to the American Society of Clinical Oncology guideline for antiemetic prophylaxis, in the first cycle of antineoplastic chemotherapy. Methods: A total of 139 chemotherapy regimens, of 105 patients, were evaluated retrospectively from 2011 to 2013. Results: We observed 78% of non-adherence to the guideline rate. The main disagreements with the directive were the prescription of higher doses of dexamethasone and excessive use of 5-HT3 antagonist for low risk emetogenic chemotherapy regimens. On univariate analysis, hematological malignancies (p=0.005), the use of two or more chemotherapy (p=0.05) and high emetogenic risk regimes (p=0.012) were factors statistically associated with greater adherence to guidelines. Treatment based on paclitaxel was the only significant risk factor for non-adherence (p=0.02). By multivariate analysis, the chemotherapy of high emetogenic risk most correlated with adherence to guideline (p=0.05). Conclusion: We concluded that the adherence to guidelines is greater if the chemotherapy regime has high emetogenic risk. Educational efforts should focus more intensely on the management of chemotherapy regimens with low and moderate emetogenic potential. Perhaps the development of a computer generated reminder may improve the adherence to guidelines. .

RESUMO Objetivo: Avaliar a adesão dos médicos prescritores, de um centro privado especializado em oncologia, à diretriz de antiêmese profilática da American Society of Clinical Oncology, no primeiro ciclo de quimioterapia antineoplásica. Métodos: Foram avaliados retrospectivamente 139 esquemas de quimioterapia, de 105 pacientes, tratados no período de 2011 a 2013. Resultados: Foram observados 78% de taxa de não adesão à diretriz. As principais discordâncias com a diretriz foram prescrição de doses mais elevadas de dexametasona e uso excessivo de antagonista 5-HT3 para regimes de quimioterapia de risco emetogênico baixo. Pela análise univariada, malignidades hematológicas (p=0,005), uso de dois ou mais quimioterápicos (p=0,05) e regimes de alto risco emetogênico (p=0,012) foram fatores estatisticamente associados a maior adesão à diretriz. O tratamento baseado em paclitaxel foi o único fator estatisticamente significativo para a não adesão (p=0,02). Pela análise multivariada, a quimioterapia de alto risco emetogênico apresentou maior correlação com a adesão à diretriz (p=0,05). Conclusão: Houve maior aderência para a quimioterapia de alto risco emetogênico. Esforços educacionais devem se concentrar mais intensamente na gestão de regimes de quimioterapia com potencial emetogênico baixo e moderado. Talvez o desenvolvimento de lembretes gerados por sistemas informatizados possa melhorar a aderência à diretriz. .

Influence of bleaching and desensitizing gel on bond strength of orthodontic brackets

OBJECTIVE: The objective of this study was to assess, in vitro, the influence of bleaching gel and the use of desensitizing agent over bond strength of ceramic brackets bonded to bovine enamel. METHODS: One hundred bovine incisors were selected and randomly divided into five groups (n = 20): Group 1, control group (without bleaching); Group 2, bleached with 35% hydrogen peroxide; Group 3, bleached with 35% hydrogen peroxide (three applications, 15 minutes each) and desensitizing agent applied for 10 minutes; Group 4, bleached with 35% hydrogen peroxide for 40 minutes; Group 5, bleached with 35% hydrogen peroxide for 40 minutes with desensitizing agent applied for 10 minutes. Brackets were bonded 7 days after bleaching and submitted to shear bond strength test after 24 hours at a compression rate of 1 mm/minute. After fracture, the adhesive remnant index (ARI) was assessed under stereoscopic at 40 x magnification. Shear strength data (MPa) were submitted to one-way ANOVA and Tukey's test with significance level set at 5%. RESULTS: Group 5 (29.33 MPa) showed significantly higher bond strength than Group 1 (19.19 MPa), Group 2 (20.59 MPa) and Group 4 (23.25 MPa), but with no difference in comparison to Group 3. There was no significant difference among the other groups. The adhesive remnant index showed predominance of score 3, that is, all resin remained adhered to enamel for all groups. CONCLUSION: Bleaching with 35% hydrogen peroxide with calcium associated with desensitizing agent application produced higher bond strength values of brackets bonded to bovine enamel. .

OBJETIVO: o objetivo do presente estudo foi avaliar, in vitro, a influência do gel clareador e da utilização de dessensibilizante na resistência adesiva de braquetes cerâmicos colados ao esmalte bovino. MÉTODOS: cem incisivos bovinos foram aleatoriamente divididos em cinco grupos (n = 20). Grupo 1, sem clareamento (controle); Grupo 2, clareamento com peróxido de hidrogênio a 35%; Grupo 3, clareamento com peróxido de hidrogênio a 35%, sendo três aplicações de 15 minutos cada, e aplicação do dessensibilizante por 10 minutos; Grupo 4, clareamento com peróxido de hidrogênio a 35% durante 40 minutos; Grupo 5, clareamento com peróxido de hidrogênio a 35% durante 40 minutos e aplicação do dessensibilizante durante 10 minutos. Os braquetes foram colados sete dias após o clareamento e submetidos ao teste de resistência ao cisalhamento após 24 horas, a uma velocidade de compressão de 1mm/minuto. Após a fratura, avaliava-se o braquete, com lupa estereoscópica, com magnificação de 40x, e o Índice de Remanescente Adesivo (IRA). Os dados de resistência ao cisalhamento (MPa) foram submetidos à análise de variância e ao teste de Tukey, com nível de significância de 5%. RESULTADOS: os resultados mostraram que as amostras do Grupo 5 apresentaram resistência de união significativamente superior à dos grupos 1, 2 e 4, mas sem diferença do Grupo 3. Não houve diferença significativa entre a resistência de união dos demais grupos. O Índice de Remanescente Adesivo mostrou predominância do escore 3, ou seja, toda resina permaneceu aderida ao esmalte, para todos os grupos. CONCLUSÃO: pôde-se concluir que o clareamento com peróxido de hidrogênio a 35%, com cálcio associado à aplicação do dessensibilizante, produziu maior resistência dos braquetes ao esmalte bovino. .