TP53 p.R337H Germline Variant among Women at Risk of Hereditary Breast Cancer in a Public Health System of Midwest Brazil.

Despite the high prevalence of TP53 pathogenic variants (PV) carriers in the South and Southeast regions of Brazil, germline genetic testing for hereditary breast cancer (HBC) is not available in the Brazilian public health system, and the prevalence of Li-Fraumeni syndrome (LFS) is not well established in other regions of Brazil. We assessed the occurrence of TP53 p.R337H carriers among women treated for breast cancer (BC) between January 2021 and January 2022 at public hospitals of Brasilia, DF, Brazil. A total of 180 patients who met at least one of the NCCN criteria for HBC underwent germline testing; 44.4% performed out-of-pocket germline multigene panel testing, and 55.6% were tested for the p.R337H variant by allelic discrimination PCR. The median age at BC diagnosis was 43.5 years, 93% had invasive ductal carcinoma, 50% had estrogen receptor-positive/HER2 negative tumors, and 41% and 11% were diagnosed respectively at stage III and IV. Two patients (1.11%) harbored the p.R337H variant, and cascade family testing identified 20 additional carriers. The TP53 p.R337H detection rate was lower than that reported in other studies from south/southeast Brazil. Nonetheless, identifying TP53 PV carriers through genetic testing in the Brazilian public health system could guide cancer treatment and prevention.

The history of families at-risk for hereditary breast and ovarian cancer: what are the impacts of genetic counseling and testing?

Introduction: Cancer Genetic Counseling (CGC) and genetic testing (GT) assume a paramount role for hereditary cancer predisposition syndrome families. We assessed the effects of CGC and GT on women affected by cancer who are at risk for hereditary breast and ovarian cancer predisposition syndrome (HBOC). Methods: This study encompasses four time points: before the CGC session, after the CGC session when blood is drawn for GT, after disclosure of GT results, and six months following disclosure of GT results. The impacts of CGC and GT were assessed using psychosocial questionnaires. Additionally, a pedigree, genogram, and ecomap were constructed through a semistructured interview. Results: A total of sixty women were included in the study. Most participants considered their perception of cancer risk to be equivalent to that of the general population, even among those with pathogenic variants. An increased perception of breast and ovarian cancer risks was associated with a heightened inclination toward religious engagement as a coping mechanism. Patients carrying variants of uncertain significance expressed greater concerns about developing another cancer compared to those who had BRCA1 and BRCA2 wild type or pathogenic variants. Qualitative analysis of the genograms and ecomaps demonstrated that the CGC/GT processes facilitate communication within families. The genogram analyses revealed the impact of CGC and GT processes on families at risk for hereditary cancer. Changes in some family relationships were observed, and an improvement in communication was noted following the GT process. Discussion: These findings can assist healthcare professionals considering a personalized approaches in clinical practice.

Emotional Impact of breast cancerrelated genetic mutation diagnosis: a systematic review / Impacto Emocional do diagnóstico de mutação genética relacionada ao câncer de mama: uma revisão sistemática

Abstract Objective Based on the premise that the diagnosis of a genetic mutation related to breast cancer causes emotional distress for the patient and their family members, a systematic literature review was conducted to clarify this relationship commonly observed in oncologic clinical practice. Method In total, 18 articles confirmed through bias analysis were reviewed. The articles were retrieved from the PubMed, Cochrane Wiley, SciELO, and APA-PsycInfo databases. Results These studies confirmed the hypothesis that a positive result in the genetic test triggers significant distress for both the patient and their family members, although each individual reacts in a unique way. The researchers recommend that the diagnosis should not be considered the sole factor for the studied outcome. It should be related to personal or family history of illness, previous experiences, and previous mental health. Conclusion We conclude, by a slight tendency, to include qualitative studies as a way to evaluate experiences in a more in-depth manner.

Resumo Objetivo Partindo da premissa que o diagnóstico de mutação genética relacionada ao câncer de mama acarreta sofrimento emocional para a paciente e seus familiares, foi realizada revisão sistemática de literatura para esclarecer essa relação comumente observada na clínica oncológica. Método Buscas realizadas nas bases PubMed, Cochrane Wiley, SciELO e APA-PsycInfo, resultaram em um total de 18 artigos, após aplicação dos critérios de inclusão, cuja boa performance foi atestada pela análise de viés. Resultados Tais estudos confirmaram a hipótese de que o resultado positivo para o teste genético desencadeia sofrimento significativo tanto para a paciente quanto para seus familiares, embora cada qual reaja de modo singular. Os pesquisadores recomendam que o diagnóstico não seja considerado fator único para o desfecho estudado, mas relacionado à história pessoal ou familiar de doenças, experiências anteriores e saúde mental prévia. Conclusão Concluímos por uma discreta tendência à inclusão de estudos qualitativos, como forma de avaliar as experiências de maneira aprofundada.

Screening for Mutations in Hereditary Cancer Susceptibility Genes in a Region with High Endogamy in Brazil.

Introduction Cancer is a multifactorial disease dependent on the influence of genetic and environmental factors. About 10% of cancers are associated with germline mutations, which predispose to a higher risk of developing cancer. Currently, the use of panels that identify susceptibility and/or association genes cancer has been increasingly used, both in clinical practice and in scientific research. Objective To investigate genetic mutations in patients with a profile for hereditary cancer in individuals from a region of northeast Brazil, where there is a high frequency of endogenous and consanguineous marriages. Methods A set of 17 genes ( BRCA1 , BRCA2 , APC , TP53 , PTEN , RET , VHL , RB1 , CDKN2 , CDH1 , CHEK2 , MLH1 , MSH2 , MSH6 , MUTYH , XPA , and XPC ) associated with cancer and hereditary syndromes were analyzed. Fifteen patients with a hereditary cancer profile were evaluated. Results The pathogenic variant found was c.1187G > A (p.Gly396Asp), rs36053993 in the MUTYH gene in a male patient diagnosed with melanoma at the age of 43 years and a family history for this tumor. This gene encodes an important enzyme related to DNA repair and has been associated with other types of cancer, this is the first report of an association with melanoma, the biological plausibility of this association is given once the MUTYH protein is expressed in the skin tissue and is responsible for repairing damage caused, for example, by sun exposure. Conclusion The results of this study suggest that this mutation may be important for the hereditary predisposition to melanoma, but a broader investigation of this mutation is needed.

Adolescent and Young Adult Understanding of Their Childhood Cancer Predisposition Diagnosis: A Qualitative Study.

We characterized germline genetic test result understanding in adolescents and young adults (AYAs) (n = 21) with cancer 1-3.9 years post-disclosure using semistructured qualitative interviews. Most AYAs articulated their cancer risk; however, 5 did not remember results and a subset demonstrated misperceptions regarding risk or confusion regarding their medical care. These findings highlight variability in AYA understanding warranting further inquiry.

Variant curation and interpretation in hereditary cancer genes: An institutional experience in Latin America.

BACKGROUND: Variant curation refers to the application of evidence-based methods for the interpretation of genetic variants. Significant variability in this process among laboratories affects clinical practice. For admixed Hispanic/Latino populations, underrepresented in genomic databases, the interpretation of genetic variants for cancer risk is challenging. METHODS: We retrospectively evaluated 601 sequence variants detected in patients participating in the largest Institutional Hereditary Cancer Program in Colombia. VarSome and PathoMAN were used for automated curation, and ACMG/AMP and Sherloc criteria were applied for manual curation. RESULTS: Regarding the automated curation, 11% of the variants (64/601) were reclassified, 59% (354/601) had no changes in its interpretation, and the other 30% (183/601) presented conflicting interpretations. With respect to manual curation, of the 183 variants with conflicting interpretations, 17% (N = 31) were reclassified, 66% (N = 120) had no changes in their initial interpretation, and 17% (N = 32) remained with conflicting interpretation status. Overall, 91% of the VUS were downgraded and 9% were upgraded. CONCLUSIONS: Most VUS were reclassified as benign/likely benign. Since false-positive and -negative results can be obtained with automated tools, manual curation should also be used as a complement. Our results contribute to improving cancer risk assessment and management for a broad range of hereditary cancer syndromes in Hispanic/Latino populations.

Identification of Germline Variants in Patients with Hereditary Cancer Syndromes in Northeast Mexico.

Hereditary cancer syndromes (HCS) are genetic diseases with an increased risk of developing cancer. This research describes the implementation of a cancer prevention model, genetic counseling, and germline variants testing in an oncologic center in Mexico. A total of 315 patients received genetic counseling, genetic testing was offered, and 205 individuals were tested for HCS. In 6 years, 131 (63.90%) probands and 74 (36.09%) relatives were tested. Among the probands, we found that 85 (63.9%) had at least one germline variant. We identified founder mutations in BRCA1 and a novel variant in APC that led to the creation of an in-house detection process for the whole family. The most frequent syndrome was hereditary breast and ovarian cancer syndrome (HBOC) (41 cases with BRCA1 germline variants in most of the cases), followed by eight cases of hereditary non-polyposic cancer syndrome (HNPCC or Lynch syndrome) (with MLH1 as the primarily responsible gene), and other high cancer risk syndromes. Genetic counseling in HCS is still a global challenge. Multigene panels are an essential tool to detect the variants frequency. Our program has a high detection rate of probands with HCS and pathogenic variants (40%), compared with other reports that detect 10% in other populations.

A Pathogenic Variant Reclassified to the Pseudogene PMS2P1 in a Patient with Suspected Hereditary Cancer.

The PMS2 gene is involved in DNA repair by the mismatch repair pathway. Deficiencies in this mechanism have been associated with Lynch Syndrome (LS), which is characterized by a high risk for colorectal, endometrial, ovarian, breast, and other cancers. Germinal pathogenic variants of PMS2 are associated with up to 5% of all cases of LS. The prevalence is overestimated for the existence of multiple homologous pseudogenes. We report the case of a 44-year-old woman diagnosed with breast cancer at 34 years without a relevant cancer family history. The presence of pathogenic variant NM_000535.7:c.1A > T, (p.Met1Leu) in PMS2 was determined by next-generation sequencing analysis with a panel of 322 cancer-associated genes and confirmed by capillary sequencing in the patient. The variant was determined in six family members (brothers, sisters, and a son) and seven non-cancerous unrelated individuals. Analysis of the amplified region showed high homology of PMS2 with five of its pseudogenes. We determined that the variant is associated with the PMS2P1 pseudogene following sequence alignment analysis. We propose considering the variant c.1A > T, (p.Met1Leu) in PMS2 for reclassification as not hereditary cancer-related, given the impact on the diagnosis and treatment of cancer patients and families carrying this variant.

Genetic Characterization in High-Risk Individuals from a Low-Resource City of Peru.

Background: Genetic testing for hereditary cancers is inconsistently applied within the healthcare systems in Latin America. In Peru, the prevalence and spectrum of cancer-predisposing germline variants is thus poorly characterized. Purpose: To determine the spectrum and prevalence of cancer-predisposing germline variants and variants of uncertain significance (VUS) in high-risk individuals located in a Peruvian low-resource setting city. Methods: Individuals presenting clinical criteria for hereditary cancer syndromes or being unaffected with familial history of cancer were included in the study. Samples from a total of 84 individuals were subjected to a high-throughput DNA sequencing assay that targeted a panel of 94 cancer predisposition genes. The pathogenicity of detected germline variants was classified according to the established American College of Medical Genetics and Genomics (ACMG) criteria. All pathogenic variants were validated by cycling temperature capillary electrophoresis. Results: We identified a total of eight pathogenic variants, found in 19 out of 84 individuals (23%). Pathogenic variants were identified in 24% (10/42) of unaffected individuals with family history of cancer and in 21% (9/42) of individuals with a cancer diagnosis. Pathogenic variants were identified in eight genes: RET (3), BRCA1 (3), SBDS (2), SBDS/MLH1 (4), MLH1 (4), TP53 (1), FANCD2 (1), DDB2/FANCG (1). In cancer cases, all colon cancer cases were affected by pathogenic variants in MLH1 and SBDS genes, while 20% (2/10) of the thyroid cancer cases by RET c.1900T>C variants were affected. One patient with endometrial cancer (1/3) had a double heterozygous pathogenic variant in DDB2 and FANCG genes, while one breast cancer patient (1/14) had a pathogenic variant in TP53 gene. Overall, each individual presented at least 17 VUS, totaling 1926 VUS for the full study population. Conclusion: We describe the first genetic characterization in a low-resource setting population where genetic testing is not yet implemented. We identified multiple pathogenic germline variants in clinically actionable predisposition genes, that have an impact on providing an appropriate genetic counselling and clinical management for individuals and their relatives who carry these variants. We also reported a high number of VUS, which may indicate variants specific for this population and may require a determination of their clinical significance.

What can we learn from more than 1,000 Brazilian patients at risk of hereditary cancer?

Background: Identifying individuals at a higher risk of developing cancer is a major concern for healthcare providers. Cancer predisposition syndromes are the underlying cause of cancer aggregation and young-onset tumors in many families. Germline genetic testing is underused due to lack of access, but Brazilian germline data associated with cancer predisposition syndromes are needed. Methods: Medical records of patients referred for genetic counseling at the Oncogenetics Department at the Hospital Sírio-Libanês (Brasília, DF, Brazil) from July 2017 to January 2021 were reviewed. The clinical features and germline findings were described. Detection rates of germline pathogenic/likely pathogenic variant (P/LPV) carriers were compared between international and Brazilian guidelines for genetic testing. Results: A total of 1,091 individuals from 985 families were included in this study. Most patients (93.5%) had a family history of cancer, including 64% with a family member under 50 with cancer. Sixty-six percent of patients (720/1091) had a personal history of cancer. Young-onset cancers (<50 years old) represented 62% of the patients affected by cancer and 17% had multiple primary cancers. The cohort included patients with 30 different cancer types. Breast cancer was the most prevalent type of cancer (52.6%). Germline testing included multigene panel (89.3%) and family variant testing (8.9%). Approximately 27% (236/879) of the tested patients harbored germline P/LPVs in cancer susceptibility genes. BRCA2, BRCA1, and TP53 were the most frequently reported genes, corresponding to 18.6%, 14.4%, and 13.5% of the positive results, respectively. Genetic testing criteria from international guidelines were more effective in identifying carriers than the Brazilian National Agency of Supplementary Health (ANS) criteria (92% vs. 72%, p<0.001). Forty-six percent of the cancer-unaffected patients who harbored a germline P/LPV (45/98) would not be eligible for genetic testing according to ANS because they did not have a family variant previously identified in a cancer-affected relative. Conclusion: The high detection rate of P/LPVs in the present study is possibly related to the genetic testing approach with multigene panels and cohort's characteristics, represented mainly by individuals with a personal or family history of young-onset cancer. Testing asymptomatic individuals with suspicious family history may also have contributed to a higher detection rate. A significant number of carriers would not have been identified using ANS criteria for genetic testing.

Characterization of genetic predisposition to molecular subtypes of breast cancer in Brazilian patients.

Introduction: BRCA1 and BRCA2 germline pathogenic variants (GPVs) account for most of the 5-10% of breast cancer (BC) that is attributable to inherited genetic variants. BRCA1 GPVs are associated with the triple negative subtype, whereas BRCA2 GPVs are likely to result in higher grade, estrogen-receptor positive BCs. The contribution of other genes of high and moderate risk for BC has not been well defined and risk estimates to specific BC subtypes is lacking, especially for an admixed population like Brazilian. Objective: The aim of this study is to evaluate the value of a multigene panel in detecting germline mutations in cancer-predisposing genes for Brazilian BC patients and its relation with molecular subtypes and the predominant molecular ancestry. Patients and methods: A total of 321 unrelated BC patients who fulfilled NCCN criteria for BRCA1/2 testing between 2016-2018 were investigated with a 94-genes panel. Molecular subtypes were retrieved from medical records and ancestry-specific variants were obtained from off-target reads obtained from the sequencing data. Results: We detected 83 GPVs in 81 patients (positivity rate of 25.2%). Among GPVs, 47% (39/83) were identified in high-risk BC genes (BRCA1/2, PALB2 and TP53) and 18% (15/83) in moderate-penetrance genes (ATM, CHEK2 and RAD51C). The remainder of the GPVs (35% - 29/83), were identified in lower-risk genes. As for the molecular subtypes, triple negative BC had a mutation frequency of 31.6% (25/79), with predominance in BRCA1 (12.6%; 10/79). Among the luminal subtypes, except Luminal B HER2-positive, 18.7% (29/155) had GPV with BRCA1/2 genes contributing 7.1% (11/155) and non-BRCA1/2 genes, 12.9% (20/155). For Luminal B HER2-positive subtype, 40% (16/40) had GPVs, with a predominance of ATM gene (15% - 6/40) and BRCA2 with only 2.5% (1/40). Finally, HER2-enriched subtype presented a mutation rate of 30.8% (4/13) with contribution of BRCA2 of 7.5% (1/13) and non-BRCA1/2 of 23% (3/13). Variants of uncertain significance (VUS) were identified in 77.6% (249/321) of the patients and the number of VUS was increased in patients with Asian and Native American ancestry. Conclusion: The multigene panel contributed to identify GPVs in genes other than BRCA1/2, increasing the positivity of the genetic test from 9.6% (BRCA1/2) to 25.2% and, considering only the most clinically relevant BC predisposing genes, to 16.2%. These results indicate that women with clinical criteria for hereditary BC may benefit from a multigene panel testing, as it allows identifying GPVs in genes that directly impact the clinical management of these patients and family members.

Hereditary Breast Cancer in the Brazilian State of Ceará (The CHANCE Cohort): Higher-Than-Expected Prevalence of Recurrent Germline Pathogenic Variants.

Purpose: There is a significant lack of epidemiological data on hereditary cancer in Northeast Brazil. This is the largest study on the prevalence and mutational spectrum of cancer predisposition genes conducted in this region and the first in the State of Ceará. Methods: Patients ≥18 years of age that were referred to CHANCE (Grupo de Câncer Hereditário do Ceará) from March 2014 to December 2020 with testing criteria for breast cancer susceptibility genes according to NCCN v.1.2021 were eligible to participate. The inclusion of patients was limited to one individual per family and to those born in the State of Ceará. All patients underwent a hereditary cancer panel testing with at least 30 genes. Results: A total of 355 patients were included, and 97 (27.3%) carried a P/LP germline variant in 18 different genes. Among the 97 P/LP carriers, BRCA1 (31, 31.9%) and BRCA2 (25, 25.7%) were the most frequently mutated genes, followed by PALB2 (10, 10.3%), CHEK2 (7, 7.2%) and ATM (4, 4.1%). A small number of recurrent variants (detected in three or more individuals) in BRCA1, BRCA2, CHEK2 and ATM represented the majority of the P/LP variants described in this cohort. Conclusion: In this cohort, the prevalence of L/PL was high, particularly involving the BRCA1, BRCA2, PALB2, CHEK2 and ATM genes and, to a lesser extent than expected, the TP53 gene. A high frequency of recurrent variants was also observed, for which further and larger analyses should clarify the presence of any possible founder effect. Characterizing the mutational profile of cancer predisposition genes in diverse populations may contribute to cancer prevention and therapeutic management.

Sociodemographic, Clinical, and Variation Outcomes for Breast Cancer and Breast Cancer-Related Mutations in a Ten-Year Cohort From Neiva, Huila, Colombia.

Background Some breast cancer cases are related to inherited mutations, and this is the reason why early mutation screening is emerging as an area of focus for cost-effective care. However, breast cancer-related mutations vary according to race, ethnicity, geographic origin, and healthcare access. Surveillance for familial breast cancer is not performed routinely in Colombia. Our main aim in this study was to describe a cohort of breast cancer patients, carrying founder breast cancer gene (BRCA) mutations, which were followed up for up to 10 years (2010-2019) in Neiva, Colombia. Methods We performed a retrospective description from an outpatient care center in Huila, Colombia, a region with high breast cancer rates. This study included patients with both a breast cancer diagnosis and an incident genetic mutation for breast cancer (detected during a breast cancer consultation). We captured information from patient medical records. Descriptive analyses were performed. Results A total of 105 patients met the study's inclusion criteria and were included patients with the BRCA1 mutation and three with BRCA2 mutations. They had a median age of 45 years (IQR, 36 to 51 years). Relatives with a breast cancer history were found in 74 carriers (70.5%). Most patients had a report of Breast Imaging-Reporting and Data System (BIRADS) ≥ 4. A TNM (tumor, node, metastasis) changed reclassification was observed in anatomical vs. prognostic classification. Median follow-up was of 74 months (IQR, 44 to 130), overall observed mortality was 22.9%, and specific mortality was 19.1%. Conclusion Women with breast cancer who carry a mutation related to breast cancer are usually younger than age 50 at diagnosis. Developing strategies and specific policies for this population is needed, and a prevalent BRCA1 c.3331_3334delCAAG mutation could be used as a cost-effective first approach. Among these patients, a risk-increased reclassification was observed.

Familial erythrocytosis 2 and von Hippel-Lindau disease in the same pediatric patient / Eritrocitosis familiar 2 y enfermedad de von Hippel-Lindau en el mismo paciente

Abstract Background: Patients with familial erythrocytosis type 2 have no increased risk of von Hippel-Lindau-associated tumors, although mutations in the VHL gene cause both pathologies. Case report: We present a case of a compound heterozygote patient with von Hippel-Lindau disease and familial erythrocytosis type 2. One of the mutations found in our patient, c.416C>G (p.Ser139Cys) of the VHL gene, has not been previously reported. This case is the second one reported where von Hippel-Lindau disease and familial erythrocytosis type 2 coexist in the same individual. Conclusions: Despite the low frequency of familial erythrocytosis type 2 in patients with von Hippel-Lindau disease, the possibility of this diagnosis should be considered to avoid unnecessary invasive studies to explain the polyglobulia in these patients and guarantee an adequate follow-up and vigilance of both diseases.

Resumen Introducción: Los pacientes con eritrocitosis familiar tipo 2 no muestran un riesgo incrementado de desarrollar tumores asociados con la enfermedad de von Hippel-Lindau, a pesar de que ambas afecciones están causadas por variantes patogénicas en el gen VHL. Caso clínico: Se presenta el caso de un paciente heterocigoto compuesto con enfermedad de von Hippel-Lindau y eritrocitosis familiar tipo 2. Una de las variantes patogénicas en el paciente, VHL c.416C>G (p.Ser139Cys), no ha sido previamente reportada. Este es el segundo reporte de caso en que la enfermedad de von Hippel-Lindau y la eritrocitosis familiar tipo 2 coexisten en el mismo individuo. Conclusiones: A pesar de la baja frecuencia de la eritrocitosis familiar tipo 2 en pacientes con enfermedad de von Hippel-Lindau, la posibilidad del diagnóstico debe considerarse con el fin de evitar estudios invasivos innecesarios para explicar la presencia de poliglobulia en estos pacientes y para garantizar un adecuado seguimiento y una correcta vigilancia de ambas enfermedades.

Expanding the phenotype of E318K (c.952G > A) MITF germline mutation carriers: case series and review of the literature.

BACKGROUND: The microphthalmia-associated transcription factor gene (MITF) belongs to the MYC supergene family and plays an important role in melanocytes' homeostasis. Individuals harboring MITF germline pathogenic variants are at increased risk of developing cancer, most notably melanoma and renal cell carcinoma. CASE PRESENTATION: We describe a cohort of ten individuals who harbor the same MITF c.952G > A (p.Glu 318Lys), or p.E318K, germline pathogenic variant. Six carriers developed at least one malignancy (4 cases of breast cancer; 1 cervical cancer; 1 colon cancer; 1 melanoma; 1 ovarian/fallopian tube cancer). A significant phenotypic heterogeneity was found among these individuals and their relatives. Breast cancer was, overall, the most frequent malignancy observed in this case series, with 13 occurrences of 60 (21.67 %) total cancer cases described among the probands and their relatives. CONCLUSIONS: Our retrospective analysis data raise the hypothesis of a possible association of the MITF p.E318K pathogenic variant with an increased risk of breast cancer.

Comprehensive analysis of germline mutations in northern Brazil: a panel of 16 genes for hereditary cancer-predisposing syndrome investigation.

BACKGROUND: Next generation sequencing (NGS) has been a handy tool in clinical practice, mainly due to its efficiency and cost-effectiveness. It has been widely used in genetic diagnosis of several inherited diseases, and, in clinical oncology, it may enhance the discovery of new susceptibility genes and enable individualized care of cancer patients. In this context, we explored a pan-cancer panel in the investigation of germline variants in Brazilian patients presenting clinical criteria for hereditary cancer syndromes or familial history. METHODS: Seventy-one individuals diagnosed or with familial history of hereditary cancer syndromes were submitted to custom pan-cancer panel including 16 high and moderate penetrance genes previously associated with hereditary cancer syndromes (APC, BRCA1, BRCA2, CDH1, CDKN2A, CHEK2, MSH2, MSH6, MUTYH, PTEN, RB1, RET, TP53, VHL, XPA and XPC). All pathogenic variants were validated by Sanger sequencing. RESULTS: We identified a total of eight pathogenic variants among 12 of 71 individuals (16.9%). Among the mutation-positive subjects, 50% were diagnosed with breast cancer and had mutations in BRCA1, CDH1 and MUTYH. Notably, 33.3% were individuals diagnosed with polyposis or who had family cases and harbored pathogenic mutations in APC and MUTYH. The remaining individuals (16.7%) were gastric cancer patients with pathogenic variants in CDH1 and MSH2. Overall, 54 (76.05%) individuals presented at least one variant uncertain significance (VUS), totalizing 81 VUS. Of these, seven were predicted to have disease-causing potential. CONCLUSION: Overall, analysis of all these genes in NGS-panel allowed the identification not only of pathogenic variants related to hereditary cancer syndromes but also of some VUS that need further clinical and molecular investigations. The results obtained in this study had a significant impact on patients and their relatives since it allowed genetic counselling and personalized management decisions.

Whole-exome sequencing of non-BRCA1/BRCA2 mutation carrier cases at high-risk for hereditary breast/ovarian cancer.

The current study aimed to identify new breast and/or ovarian cancer predisposition genes. For that, whole-exome sequencing (WES) was performed in the germline DNA of 52 non-BRCA1/BRCA2/TP53 mutation carrier women at high-risk for hereditary breast and ovarian cancer (HBOC). All variants were classified using information from population and disease specific databases, in silico prediction tools and the American College of Medical Genetics and Genomics (ACMG) criteria. Loss of heterozygosity (LOH) of tumor samples and segregation analyses were performed whenever possible. The variants identified were investigated in a second, independent cohort of 17 BC cases. Pathogenic/Likely Pathogenic variants were identified in known cancer genes such as CHEK2, MUTYH, PMS2, and RAD51C. Rare and potentially pathogenic variants were identified in DNA repair genes (FAN1, POLQ, and RAD54L) and other cancer-related genes such as DROSHA and SLC34A2. Interestingly, the variant c.149T>G in the FAN1 gene was identified in two unrelated families, and exhibited LOH in the tumor tissue of one of them. In conclusion, this is the largest Brazilian WES study involving families at high-risk for HBOC which has brought novel insights into the role of potentially new genetic risk factors for hereditary breast and ovarian cancer.

Prevalence of germline variants in consensus moderate-to-high-risk predisposition genes to hereditary breast and ovarian cancer in BRCA1/2-negative Brazilian patients.

PURPOSE: This study aimed to identify and classify genetic variants in consensus moderate-to-high-risk predisposition genes associated with Hereditary Breast and Ovarian Cancer Syndrome (HBOC), in BRCA1/2-negative patients from Brazil. METHODS: The study comprised 126 index patients who met NCCN clinical criteria and tested negative for all coding exons and intronic flanking regions of BRCA1/2 genes. Multiplex PCR-based assays were designed to cover the complete coding regions and flanking splicing sites of six genes implicated in HBOC. Sequencing was performed on HiSeq2500 Genome Analyzer. RESULTS: Overall, we identified 488 unique variants. We identified five patients (3.97%) that harbored pathogenic or likely pathogenic variants in four genes: ATM (1), CHEK2 (2), PALB2 (1), and TP53 (1). One hundred and thirty variants were classified as variants of uncertain significance (VUS), 10 of which were predicted to disrupt mRNA splicing (seven non-coding variants and three coding variants), while other six missense VUS were classified as probably damaging by prediction algorithms. CONCLUSION: A detailed mutational profile of non-BRCA genes is still being described in Brazil. In this study, we contributed to filling this gap, by providing important data on the diversity of genetic variants in a Brazilian high-risk patient cohort. ATM, CHEK2, PALB2 and TP53 are well established as HBOC predisposition genes, and the identification of deleterious variants in such actionable genes contributes to clinical management of probands and relatives.

Using Co-segregation and Loss of Heterozygosity Analysis to Define the Pathogenicity of Unclassified Variants in Hereditary Breast Cancer Patients.

The use of gene panels introduces a new dilemma in the genetics field due to the high frequency of variants of uncertain significance (VUS). The objective of this study was to provide evidence that may help in the classification of these germline variants in terms of their clinical impact and association with the disease in question. A total of 52 unrelated women at-risk for HBOC and negative for BRCA1/BRCA2 pathogenic variants were evaluated through a gene panel comprising 14 breast and/or ovarian cancer susceptibility genes. Of the 453 germline variants identified, 15 variants (classes 3, 4, and 5) in the ATM, BRIP1, CHEK2, MRE11A, MUTHY, PALB2, RAD50, and RAD51C genes were evaluated via databases, co-segregation studies and loss of heterozygosity in the tumor. The co-segregation analysis allowed the establishment of an association with the presence of variants and the risk of cancer for variant c.316C>T in the BRIP1 gene. Four variants of uncertain significance showed loss of heterozygosity in the tumor (ATM c.4709T>C; CHEK2 c.1036C>T; PALB2 c.1001A>G, and RAD50 c.281T>C), which is an indication of pathogenicity. Thus, the present study provides novel evidence that favors the association of variants in moderate-risk genes with the development of hereditary breast cancer.

Clinical and Molecular Assessment of Patients with Lynch Syndrome and Sarcomas Underpinning the Association with MSH2 Germline Pathogenic Variants.

Lynch syndrome (LS) is a hereditary cancer-predisposing syndrome associated most frequently with epithelial tumors, particularly colorectal (CRC) and endometrial carcinomas (EC). The aim of this study was to investigate the relationship between sarcomas and LS by performing clinical and molecular characterization of patients presenting co-occurrence of sarcomas and tumors from the LS spectrum. We identified 27 patients diagnosed with CRC, EC, and other LS-associated tumors who had sarcomas in the same individuals or families. Germline genetic testing, mismatch repair (MMR) protein immunohistochemistry, microsatellite instability (MSI), and other molecular analyses were performed. Five LS patients presenting personal or family history of sarcomas were identified (3 MSH2 carriers and 2 MLH1), with 2 having Muir-Torre phenotypes. For two MSH2 carriers we confirmed the etiology of the sarcomas (one liposarcoma and two osteosarcomas) as LS-related, since the tumors were MSH2/MSH6-deficient, MSI-high, or presented a truncated MSH2 transcript. Additionally, we reviewed 43 previous reports of sarcomas in patients with LS, which revealed a high frequency (58%) of MSH2 alterations. In summary, sarcomas represent a rare clinical manifestation in patients with LS, especially in MSH2 carriers, and the analysis of tumor biological characteristics can be useful for definition of tumor etiology and novel therapeutic options.