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.

Oncogenetics service and the Brazilian public health system: the experience of a reference Cancer Hospital.

The identification of families at-risk for hereditary cancer is extremely important due to the prevention potential in those families. However, the number of Brazilian genetic services providing oncogenetic care is extremely low for the continental dimension of the country and its population. Therefore, at-risk patients do not receive appropriate assistance. This report describes the creation, structure and management of a cancer genetics service in a reference center for cancer prevention and treatment, the Barretos Cancer Hospital (BCH). The Oncogenetics Department (OD) of BCH offers, free of charge, to all patients/relatives with clinical criteria, the possibility to perform i) genetic counseling, ii) preventive examinations and iii) genetic testing with the best quality standards. The OD has a multidisciplinary team and is integrated with all specialties. The genetic counseling process consists (mostly) of two visits. In 2014, 614 individuals (371 families) were seen by the OD. To date, over 800 families were referred by the OD for genetic testing. The support provided by the Oncogenetics team is crucial to identify at-risk individuals and to develop preventive and personalized behaviors for each situation, not only to the upper-middle class population, but also to the people whose only possibility is the public health system.

Genotype-phenotype correlation in 99 familial adenomatous polyposis patients: A prospective prevention protocol.

BACKGROUND: Familial adenomatous polyposis (FAP) is a syndrome caused by germline pathogenic variants in the tumor suppressor gene adenomatous polyposis coli (APC). Identification of APC pathogenic variants sites and the genotype-phenotype correlation are important for characterizing, monitoring, and treating members of affected families. The aim of this study was to correlate genotype-phenotype of Brazilian individuals carrying APC pathogenic germline variants and that have FAP. METHODS: The polyposis phenotype of 99 individuals from 35 families between July 2013 and December 2014 were prospectively evaluated based on the InSIGHT polyposis staging classification. Seven extra-colonic manifestations were assessed and the clinical manifestations correlated with the APC genotype. RESULTS: The age of the study participants ranged from 12 to 67 years (median of 29 years). Twenty-six APC pathogenic variants were identified. Fifty-five cases harbored nonsense pathogenic variants (55.6%). Frameshift alterations were noted in 39 cases (39.4%). Aberrant splicing was noted in 1 case (1%). Rearrangements were observed in 3 cases (3%). An association between nonsense variants and rearrangement was noted in 1 case (1%). The genotype-phenotype correlation analysis led the identification of classic FAP in 94 cases (94.9%). Profuse polyposis was identified in 5 cases (5.1%). Thirty-six cases were diagnosed with cancer of which 29 cases (80.6%) were colorectal cancer, 1 case (2.7%) was brain cancer, 4 cases (11.2%) were papillary thyroid cancer, and 2 cases (5.5%) were stomach cancer. The extra-colonic manifestations included 9 individuals with desmoids tumors, 10 with osteomas, and 9 with congenital hypertrophy of the retinal pigment epithelium. CONCLUSIONS: The genotype-phenotype correlation in Brazilian individuals with FAP revealed specific findings not previously reported for other cohorts, demonstrating the relevance of knowledge regarding the variable pathogenic variants and clinical presentation in different populations for adequate individual clinical management of patients harboring this medical condition.

Prevalence of BRCA1/BRCA2 mutations in a Brazilian population sample at-risk for hereditary breast cancer and characterization of its genetic ancestry.

BACKGROUND: There are very few data about the mutational profile of families at-risk for hereditary breast and ovarian cancer (HBOC) from Latin America (LA) and especially from Brazil, the largest and most populated country in LA. RESULTS: Of the 349 probands analyzed, 21.5% were BRCA1/BRCA2 mutated, 65.3% at BRCA1 and 34.7% at BRCA2 gene. The mutation c.5266dupC (former 5382insC) was the most frequent alteration, representing 36.7% of the BRCA1 mutations and 24.0% of all mutations identified. Together with the BRCA1 c.3331_3334delCAAG mutation, these mutations constitutes about 35% of the identified mutations and more than 50% of the BRCA1 pathogenic mutations. Interestingly, six new mutations were identified. Additionally, 39 out of the 44 pathogenic mutations identified were not previously reported in the Brazilian population. Besides, 36 different variants of unknown significance (VUS) were identified. Regarding ancestry, average ancestry proportions were 70.6% European, 14.5% African, 8.0% Native American and 6.8% East Asian. MATERIALS AND METHODS: This study characterized 349 Brazilian families at-risk for HBOC regarding their germline BRCA1/BRCA2 status and genetic ancestry. CONCLUSIONS: This is the largest report of BRCA1/BRCA2 assessment in an at-risk HBOC Brazilian population. We identified 21.5% of patients harboring BRCA1/BRCA2 mutations and characterized the genetic ancestry of a sample group at-risk for hereditary breast cancer showing once again how admixed is the Brazilian population. No association was found between genetic ancestry and mutational status. The knowledge of the mutational profile in a population can contribute to the definition of more cost-effective strategies for the identification of HBOC families.

Experimental infection of suckling mice by subcutaneous inoculation with Oropouche virus.

Oropouche virus, of the family Bunyaviridae, genus Orthobunyavirus, serogroup Simbu, is an important causative agent of arboviral febrile illness in Brazil. An estimated 500,000 cases of Oropouche fever have occurred in Brazil in the last 30 years, with recorded cases also in Panama, Peru, Suriname and Trinidad. We have developed an experimental model of Oropouche virus infection in neonatal BALB/c mouse by subcutaneous inoculation. The vast majority of infected animals developed disease on the 5th day post infection, characterized mainly by lethargy and paralysis, progressing to death within 10 days. Viral replication was documented in brain cells by in situ hybridization, immunohistochemistry and virus titration. Multi-step immunohistochemistry indicated neurons as the main target cells of OROV infection. Histopathology revealed glial reaction and astrocyte activation in the brain and spinal cord, with neuronal apoptosis. Spleen hyperplasia and mild meningitis were also found, without viable virus detected in liver and spleen. This is the first report of an experimental mouse model of OROV infection, with severe involvement of the central nervous system, and should become useful in pathogenesis studies, as well as in preclinical testing of therapeutic interventions for this emerging pathogen.