Phenocopy in a patient with triple negative breast cancer: a case report

ABSTRACT A total of 1.67 million breast cancer cases per year are reported worldwide. Of these, 5%-10% are caused by inherited mutations. Phenocopy is a rare phenomenon, with only a few cases reported in the literature. In phenocopies, phenotypes identical to those with genetic origin occur because of environmental factors rather than familial mutations. We describe a case of phenocopy in a 44-year-old female patient with triple-negative breast cancer. The mother and sister wee heterozygous for c.1813delA, p.Ile605TyrfsTer9 in BRCA2 . The patient underwent genetic testing for BRCA1 and BRCA2 and exome sequencing. Familial or other cancer variants were not detected. The most accepted phenocopy theory is that patients without genetic variants but who are carriers of these mutations undergo cellular changes due to environmental factors, increasing the risk of breast cancer. Therefore, the detection of phenocopy in patients with breast cancer is important in clinical practice.

Tamizaje para cáncer de mama con resonancia magnética en mujeres portadoras de mutaciones BRCA y no-BRCA / Magnetic resonance imaging breast cancer screening in women who are carriers of BRCA and non-BRCA gene mutations / Rastreamento de câncer de mama com ressonância magnética em mulheres com mutações BRCA e não BRCA

Introducción: la predisposición hereditaria causada por mutaciones patogénicas de la línea germinal (MPG) explica hasta el 10% de los cánceres de mama. Para reducir su impacto en mujeres mutadas se han propuesto diferentes estrategias, tales como las cirugías reductoras de riesgo o el screening con resonancia magnética (RM) de mamas. Métodos: en este estudio observacional retrospectivo se analizaron los registros de mujeres portadoras de MPG para evaluar las diferentes acciones tomadas luego del test genético. A las pacientes no mastectomizadas se les recomendó ingresar a un programa anual de cribado con RM y se evaluó el porcentaje de adherencia al plan, el número de biopsias efectuadas y el número de cánceres de mama detectados. Resultados: se incluyeron 134 mujeres con MPG, con una distribución en tercios iguales de los genes BRCA1, BRCA2 y genes no-BRCA. Entre las mutadas con indicación de seguimiento, 64% ingresaron al programa de cribado con RM. Las razones que llevaron a las mujeres a no ingresar al programa de seguimiento fueron: la oposición del médico tratante (53%), oposición de la paciente (38%), y falta de recursos (9%). Se realizaron seis biopsias por hallazgos en la RM entre las cuales se detectó un cáncer de mama. La incidencia de cáncer fue de 11 cada 1.000 mujeres-años de riesgo. Conclusiones: nuestro programa de seguimiento con RM de pacientes mutadas logró captar un porcentaje alto de candidatas. Una proporción significativa de las mujeres no ingresó debido la desaprobación del médico tratante o de la propia paciente. La evidencia obtenida revela una necesidad imperiosa de reforzar los programas educativos que destaquen la importancia del seguimiento con RM de las pacientes de alto riesgo en nuestro país.

Summary: Introduction: genetic propensity caused by germline pathogenic mutations explain up to 10% of breast cancer cases. Different strategies have been proposed to reduce its impact on women who are carriers of mutations, such as risk-reducing surgeries or breast magnetic resonance screening. Method: observational, retrospective study analyzing the medical records of women who are carriers of germline pathogenic mutations to assess the different measures taken after the genetic test. Non-mastectomized patients were advised to join an annual MRI screening program and the percentage of adherence to plan was evaluated, along with biopsies performed and the number of breast cancer cases detected. Results: 134 women carriers of germline pathogenic mutations were included in the study, with equal distributions in thirds for BRCA1, BRCA2 and non-BRCA genes. 64% of carriers of mutations who were subject to follow-up checkups joined the RMI screening program. The reasons why women failed to join the follow-up program were: the treating physician objected to the program (53%), the patients opposed to program (38%) and lack of resources (9%). Six biopsies were performed as a consequence of findings in the RMI, and one case of breast cancer was detected. Cancer incidence was 11 out of 1000 women - risk years. Conclusions: our RMI follow-up program for women who are carriers of mutations managed to attract a high percentage of candidates. A significant amount of women failed to join the program because of their treating physician's or their own disapproval. Evidence obtained reveals the dramatic need to reinforce educational programs that emphasize on the importance of RMI follow-up of high risk patients in our country.

Introdução: a predisposição hereditária causada por mutações germinativas patogênicas (GMP) explica até 10% dos cânceres de mama. Para reduzir seu impacto em mulheres com mutações, diferentes estratégias têm sido propostas, como cirurgias de redução de risco ou ressonância magnética (RM) das mamas. Métodos: neste estudo observacional retrospectivo, os registros de mulheres portadoras de MPG foram analisados para avaliar as diferentes ações tomadas após o teste genético. Pacientes não mastectomizadas foram recomendadas a entrar em um programa anual de triagem por ressonância magnética e foram avaliados o percentual de adesão ao plano, o número de biópsias realizadas e o número de cânceres de mama detectados. Resultados: foram incluídas 134 mulheres com MPG, com uma distribuição de terços iguais dos genes BRCA1, BRCA2 e não-BRCA. Entre as mulheres com mutações com indicação de acompanhamento, 64% entraram no programa de triagem por ressonância magnética. Os motivos que levaram as mulheres a não ingressarem ao programa de acompanhamento foram: oposição do médico assistente (53%), oposição da paciente (38%) e falta de recursos (9%). Seis biópsias foram realizadas devido a achados de ressonância magnética, entre os quais foi detectado um câncer de mama. A incidência de câncer foi de 11 por 1.000 mulheres-ano de risco. Conclusões: nosso programa de acompanhamento de ressonância magnética para pacientes com mutação conseguiu capturar uma alta porcentagem de candidatas. Uma proporção significativa de mulheres não entrou devido à falta de aprovação do médico assistente ou da própria paciente. As evidências obtidas revelam a necessidade urgente de reforçar programas educacionais que destaquem a importância do acompanhamento por RM de pacientes de alto risco no Uruguai.

Implicações éticas dos testes genéticos de suscetibilidade ao câncer de mama / Ethical implications of genetic testing of susceptibility to breast cancer / Implicaciones éticas de las pruebas genéticas de susceptibilidad al cáncer de mama

Resumo O câncer de mama representa um problema de saúde pública por ser a neoplasia maligna de maior incidência em mulheres no mundo. A forma hereditária corresponde a cerca de 5% a 10% de todos os casos e está diretamente relacionada à herança de mutações genéticas, sendo as principais nos genes supressores de tumor BRCA1 e BRCA2. A identificação dessas mutações é de extrema importância pelo elevado risco de desenvolvimento de câncer de mama nessa população, permitindo estratégias de rastreamento diferenciado e adoção de medidas de redução de risco. Entretanto, é importante e necessário refletir sobre os aspectos éticos relacionados ao uso indiscriminado de testes genéticos. O objetivo deste trabalho foi avaliar o conhecimento e a opinião de médicos de um centro de referência oncológico sobre a indicação dos testes genéticos de suscetibilidade ao câncer de mama mediante dilemas éticos aos quais são submetidos na prática médica.

Abstract Breast cancer is a public health problem because it is the malignant neoplasm with the highest incidence in women worldwide. The hereditary form corresponds to about 5% to 10% of all cases and is directly related to the inheritance of genetic mutations. The main ones occur in the BRCA1 and BRCA2 tumor suppressor genes. The identification of these mutations is extremely important because of the high risk of breast cancer development in this population, allowing differentiated screening strategies and the adoption of risk reduction measures. However, reflections on the ethical aspects related to the indiscriminate use of genetic testing are important and necessary. The objective of this study was to evaluate the knowledge and opinion of physicians of an oncology reference center on the indication of genetic tests for susceptibility to breast cancer given the ethical dilemmas to which they are submitted in medical practice.

Resumen El cáncer de mama representa un problema de salud pública, ya que es la neoplasia maligna con mayor incidencia en las mujeres de todo el mundo. La forma hereditaria corresponde a entre el 5% y el 10% de todos los casos y está directamente relacionada con la herencia de mutaciones genéticas, y las principales se dan en los genes supresores de tumores BRCA1 y BRCA2. La identificación de estas mutaciones es extremadamente importante debido al elevado riesgo de esta población de desarrollar cáncer de mama, además de permitir estrategias de rastreo diferenciadas y la adopción de medidas de reducción del riesgo. Sin embargo, es importante y necesario reflexionar sobre los aspectos éticos relacionados con el uso indiscriminado de las pruebas genéticas. El objetivo de este estudio fue evaluar el conocimiento y la opinión de los médicos de un centro oncológico de referencia sobre la indicación de las pruebas genéticas de susceptibilidad al cáncer de mama mediante los dilemas éticos a los que se ven sometidos en la práctica médica.

Correlation between the number of false positive variants and the quality of results using Ion Torrent PGM™ sequencing to screen BRCA genes / Correlación entre el número de variantes de falsos positivos y la calidad de los resultados en la secuenciación con Ion Torrent PGM™ para seleccionar genes BRCA

Abstract | Introduction: Next Generation Sequencing (NGS) is cost-effective and a faster method to study genes, but its protocol is challenging. Objective: To analyze different adjustments to the protocol for screening the BRCA genes using Ion Torrent PGM sequencing and correlate the results with the number of false positive (FP) variants. Materials and methods: We conducted a library preparation process and analyzed the number of FP InDels, the library concentration, the number of cycles in the target amplification step, the purity of the nucleic acid, the input, and the number of samples/Ion 314 chips in association with the results obtained by NGS. Results: We carried out 51 reactions and nine adjustments of protocols and observed eight FP InDels in homopolymer regions. No FP Single-Nucleotide Polymorphism variant was observed; 67.5% of protocol variables were jointly associated with the quality of the results obtained (p<0.05). The number of FP InDels decreased when the quality of results increased. Conclusion: The Ion AmpliSeq BRCA1/BRCA2 Community Panel had a better performance using four samples per Ion-314 chip instead of eight and the optimum number of cycles in the amplification step, even when using high-quality DNA, was 23. We observed better results with the manual equalization process and not using the Ion Library Equalizer kit. These adjustments provided a higher coverage of the variants and fewer artifacts (6.7-fold). Laboratories must perform internal validation because FP InDel variants can vary according to the quality of results while the NGS assay should be validated with Sanger.

Resumen | Introducción. La secuenciación de nueva generación es un método rentable y rápido para el estudio de los genes, pero su protocolo entraña desafíos. Objetivo. Investigar diferentes ajustes del protocolo de selección de los genes BRCAmediante secuenciación de Ion Torrent PGM™ y correlacionar los resultados con el número de variantes de falso positivo. Materiales y métodos. El proceso de preparación de la biblioteca, el número de falsos positivos InDels, la concentración de la biblioteca, el número de ciclos en el paso de amplificación de objetivos, la pureza del ácido nucleico, la entrada y el número de muestras por chip del Ion-314 se analizaron en asociación con los resultados obtenidos por secuenciación de nueva generación secuenciación de nueva generación. Resultados. Se hicieron 51 reacciones y nueve ajustes de los protocolos, y se observaron ocho falsos positivos InDels en las regiones de homopolímeros. No se observó ninguna variante de polimorfismo de nucleótido simple falso positivo. En 67,5 % de los casos, las variables de protocolo en su conjunto se asociaron con la calidad de los resultados obtenidos (p<0,05). El número de falsos positivos InDels disminuyó al aumentar la calidad de los resultados. Conclusiones. El panel comunitario Ion AmpliSeq BRCA1/BRCA2 tuvo un mejor rendimiento, con cuatro muestras por chip Ion-314 en lugar de ocho, y el número de ciclos en el paso de amplificación, incluso con ADN de alta calidad, fue mejor con 23. Se observaron mejores resultados con el proceso de ecualización manual y sin el uso del kit Ion Library Equalizer. Estos ajustes proporcionaron una mayor cobertura de las variantes y menos artefactos. Los laboratorios deben realizar la validación interna porque las variantes de falsos positivos InDel pueden variar según la calidad de los resultados. La secuenciación de próxima generación debe validarse con Sanger.

BRCA gene detection for cancer prevention and management in the high risk population / 中华全科医师杂志

Breast cancer susceptibility gene (BRCA) is a tumor suppressor gene. The carriers of BRCA mutation have a significantly higher risk of breast, ovarian, pancreatic, prostate and rectal cancers than the general population. BRCA gene detection can effectively evaluate the risk of relevant malignant tumors. In this article, the recent research progress on the relationship between BRCA gene mutations and related cancers is summarized, and the roles of BRCA gene testing in the prevention and management of relevant malignant tumors are discussed.

Expressions of breast cancer susceptibility gene 1 and tubulin β3 in gastric cancer and their clinical significances / 肿瘤研究与临床

Objective:To investigate the expressions and clinical significances of breast cancer susceptibility gene 1 (BRCA1) and tubulin β3 (TUBB3) in patients with gastric cancer, so as to provide a basis for accurate diagnosis and treatment of gastric cancer.Methods:The data of 46 hospitalized patients with gastric cancer who underwent gastroscopebiopsy or operation in Maanshan People's Hospital in Anhui Province from December 2018 to May 2020 were collected. The expressions of BRCA1 and TUBB3 in tumor tissues and peritumoral tissues were determined by immunohistochemistry. Real-time fluorescent quantitative polymerase chain reaction (qRT-PCR) was used to detect BRCA1 and TUBB3 mRNA expressions in tumor tissues and peritumoral tissues. The correlations between expressions of BRCA1 and TUBB3 in gastric cancer tissues and clinicopathologic features were analyzed.Results:The positive rates of BRCA1 and TUBB3 proteins in gastric cancer tissues were higher than those in peritumoral tissues [43.5% (20/46) vs. 16.7% (5/30), 65.2% (30/46) vs. 6.7% (2/30), both P < 0.05]. qRT-PCR showed that the relative expression of BRCA1 mRNA in gastric cancer tissues was higher than that in peritumoral tissues (15.5±6.8 vs. 5.0±1.6, t = 9.41, P < 0.01); the relative expression of TUBB3 mRNA in gastric cancer tissues was higher than that in peritumoral tissues (22.1±6.3 vs. 5.7±1.9, t = 3.51, P < 0.01). The positive rate of TUBB3 protein in female patients was lower than that in male patients [15.4% (2/13) vs. 84.8% (28/33)], the positive rate of BRCA1 protein in patients with positive human epidermal growth factor receptor 2 (HER2) was higher than that in patients with negative HER2 [87.5% (7/8) vs. 47.4% (18/38)], the positive rate of BRCA1 protein in patients with family history was higher than that in patients without family history [85.7% (6/7) vs. 35.9% (14/39)], and the differences were statistically significant (all P < 0.05). The positive expressions of BRCA1 and TUBB3 proteins in gastric cancer tissues were both correlated with tumor stage and differentiation (all P < 0.05), and the expressions of BRCA1 and TUBB3 proteins were correlated ( χ2 = 33.52, P < 0.01). Conclusions:BRCA1 and TUBB3 may be related to the occurrence and development of gastric cancer, and there may be a certain relationship between BRCA1 and TUBB3, BRCA1 and HER2. BRCA1 and TUBB3 may have significances in the diagnosis and treatment of gastric cancer.

Comparison of hereditary breast and ovarian cancer syndrome and sporadic ovarian cancer in ovarian cancer BRCA mutations / 中华妇产科杂志

Objective:To study the difference between BRCA gene mutations in hereditary breast and ovarian cancer syndrome (HBOC) and in sporadic ovarian cancer (SOC).Methods:This study was for exploratory research, the inclusion criteria were 284 patients with ovarian cancer admitted at Shanxi Provincial Cancer Hospital from November 2018 to December 2019, with high-throughput DNA sequencing including the full coding regions and exon-intron link regions of BRCA1 and BRCA2 gene. Pathogenic mutations in the BRCA gene of patients with ovarian cancer were collected and mutation site analysis was performed to compare phenotypic differences in pathogenic mutations between HBOC syndrome and SOC patients.Results:(1) Of the 284 ovarian cancer patients, seventy-seven had BRCA pathogenic mutations with a mutation rate of 27.1% (77/284), with BRCA1 mutation rate of 19.7% (56/284), BRCA2 gene 6.7% (19/284) and BRCA1/2 common mutation rate of 0.7% (2/284). Of the 284 patients with ovarian cancer, the pathogenic mutation rate in the BRCA gene in HBOC syndrome patients was 43.8% (32/73), which were significantly higher than that in SOC patients [21.3% (45/211); χ2=13.905, P<0.01]. Among BRCA1 gene mutation, the mutation rate in HBOC syndrome was higher than that of SOC [87.5% (28/32) vs 62.2% (28/45)], the BRCA2 gene mutation rate in patients with HBOC syndrome was lower than that in SOC patients [6.2% (2/32) vs 37.8% (17/45)], and there were statistically significant differences (all P<0.05). Two of the 77 patients with pathogenic mutations in the BRCA gene were multisite mutations, including one simultaneous two site mutation, one simultaneous three site mutation. There were 80 mutation sites with frameshift deletion mutations (55.0%, 44/80) and nonsense mutations (31.2%, 25/80). (2) Of the 73 patients with HBOC syndrome, 32 cases had pathogenic mutations in BRCA gene, including 28 cases in BRCA1, mainly in exon 11 and 24 (9 and 7 cases, respectively), and only two cases in BRCA2, both in exon 11; another two had multiple locus mutations. Of the 211 patients with SOC, 45 cases had pathogenic mutants in BRCA gene, including 28 cases in BRCA1, mainly in exon 11 and 24 (15 and 2 cases, respectively), and 17 cases in BRCA2, mainly in exon 11 (11 cases). (3) Thirty-four pathogenic mutation sites in BRCA gene were found newly, twenty of them were located in the BRCA1 gene, including a locus located on the intron 6, 301+1G>A, and the remaining 19 sites were located on the exons, including 283_286delCTTG, 68_69delAG, 132C>T, 514_547+3del37, 742delA, 1126_1129delAATA, 1196delA, 1352_1364del, 1465G>T, 2171delC, 2341G>T, 3359_3363delTTAAT, 4085_4086ins11, 4161_4162delTC, 4165_4166delAG, 4258G>T, 4338_4339del8insAGAA, 4468G>T, and 4783delA; fourteen sites were located in the BRCA2 gene, including a locus located on the intron 7, 631+1G>A, and the remaining 13 sites were located on the exons, including 2648delT, 2914A>T, 2950_2951insG, 4357+1G>A, 5054C>T, 5257A>T, 5291_5292insTC, 5913delT, 3593delA, 6091_6092insA, 6135_6136delTT, 7452delT, 9097_9098insA. A tal of 28 repeat mutations were located in the BRCA1 gene; among them, the site 5470_5477del8 was repeated 6 times, while 3 times in 981_982delAT. Conclusions:Patients with HBOC syndrome have a significantly higher rate of pathogenic mutation in the BRCA gene than that in patients with SOC. BRCA gene pathogenic mutation sites in HBOC syndrome patients occur commonly in exon 11 and 24 of BRCA 1 gene, while SOC patients occur mainly in exon 11 and 24 of BRCA1 gene and exon 11 of BRCA2 gene. The two loci of BRCA1∶5470_5477del8, BRCA1∶981_982delAT may be ancestor mutations in Chinese ovarian cancer patients, and 34 newly discovered pathogenic mutations in the BRCA gene, enriching the BRCA gene mutation spectrum in the Chinese population.

Pathogenic variants in BRCA1/2 genes among patients with triple-negative breast cancer: a case series

Triple-negative breast cancer (TNBC) is an uncommon molecular subtype (representing 15%­20% of breast cancers) characterized by the non-expression of estrogen receptor, progesterone receptor, and human epidermal growth receptor factor 2. More aggressive and lethal, TNBC is often associated with pathogenic variants in BRCA1/2 genes. This study aimed to describe a series of seven cases of patients with TNBC and pathogenic variants in BRCA1/2 genes. All patients were female and under 50 years of age at diagnosis. Four of them presented a family history of breast cancer and/or other neoplasms. The predominant clinical stage was IIB, and the main anatomopathological stage was pT2pN0M0. The mean tumor size in the series was 2.5 cm (1.0 to 3.2 cm). Ki-67 was > 30% in all patients. Three cases (43%) had pathological complete response, and only one presented extensive residual disease after neoadjuvant chemotherapy. Six patients showed pathogenic variants in BRCA1 (86%) and one in BRCA2+ (14%). After a mean follow-up of 38 months (19 to 68 months), five patients were alive and without neoplastic disease, and two progressed to metastasis.

Cáncer de mama en seis familias del Tolima y el Huila: mutación BRCA1 3450del4 / Breast cancer in six families from Tolima and Huila: BRCA1 3450del4 mutation

Introducción. El cáncer de mama es un problema mundial de salud pública; entre el 5 y el 10 % de los casos presentan agregación familiar, lo que se explicaría por la presencia de mutaciones en genes de alto riesgo como el BRCA1 y el BRCA2. El origen fundador de la deleción BRCA1 3450del4 en Colombia ya fue reportado. Objetivo. Hacer un análisis descriptivo de seis familias del del Tolima y del Huila con la deleción BRCA1 3450del4 de la asociación de la mutación germinal, con el cáncer de mama y la agregación familiar. Materiales y métodos. Se hizo un estudio descriptivo y transversal de seis casos índice con cáncer de mama positivos para BRCA1 3450del4, que cumplían tres de los criterios establecidos por Jalkh, et al. A partir de la información de las entrevistas, se realizaron los árboles genealógicos (GenoPro™, versión 2016). Se tipificó la mutación en familiares sanos y afectados que aceptaron participar. Resultados. De los 78 individuos seleccionados por conveniencia en las seis familias, 30 presentaron la mutación BRCA1 3450del4; de ellos, seis tenían cáncer de mama, uno, cáncer de ovario, uno, cáncer de mama y ovario, y otro, cáncer de próstata; 21 no presentaban neoplasias. De los 30 individuos portadores de la variante patogénica, seis eran hombres y 24 mujeres, 13 de ellas menores de 30 años. Conclusiones. En este estudio se confirmó la asociación de la deleción BRCA1 3450del4 con el cáncer de mama de agregación familiar.

Introduction: Breast cancer is a worldwide public health problem; between 5% and 10% of the cases present familial aggregation explained by genes of high risk such as BRCA1and BRCA2. The founding origin of the deletion BRCA1 3450del4 in Colombia has been previously reported. Objective: To carry out in six families from Tolima and Huila departments a descriptive analysis of the presence of the BRCA1 3450del4 mutation associated with breast cancer and familial aggregation. Materials and methods: We conducted a descriptive and cross-sectional study of six index cases with breast cancer positive for BRCA1 3450del4 that fulfilled three of the criteria established by Jalkh, et al. The genealogical trees were made using the information of the interview data (GenoPro™, version 2016). The mutation was typified in healthy and affected relatives who agreed to participate. Results: Thirty of the 78 individuals selected by convenience in the six families presented the mutation BRCA1 3450del4 six of whom developed breast cancer, one, ovarian cancer, one ovarian and breast cancer, and one prostate cancer; 21 did not present any type of neoplasm at the time of the study. Of the 30 individuals carrying the pathogenic variant, six were men, 24 were women, and 13 of these were under 30. Conclusions: In this study of families with the deletion BRCA1 3450del4 in Tolima and Huila we confirmed its association with familial aggregation of breast cancer.

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.