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.

Genetic Variants in the 3'UTR of BRCA1 and BRCA2 Genes and their Putative Effects on the microRNA Mechanism in Hereditary Breast and Ovarian Cancer.

Hereditary breast and ovarian cancer (HBOC) syndrome is mainly caused by mutations in the BRCA1 and BRCA2 genes. The 3'UTR region allows for the binding of microRNAs, which are involved in genetic tune regulation. We aimed to identify allelic variants on 3'UTR miRNA-binding sites in the BRCA1 and BRCA2 genes in HBOC patients. Blood samples were obtained from 50 patients with HBOC and from 50 controls. The 3'UTR regions of BRCA1 and BRCA2 were amplified by PCR and sequenced to identify genetic variants using bioinformatics tools. We detected nine polymorphisms in 3'UTR, namely: four in BRCA1 (rs3092995 (C/G), rs8176318 (C/T), rs111791349 (G/A), and rs12516 (C/T)) and five in BRCA2 (rs15869 (A/C), rs7334543 (A/G), rs1157836 (A/G), and rs75353978 (TT/del TT)). A new variant in position c.*457 (A/C) on 3'UTR of BRCA2 was also identified. The following three variants increased the risk of HBOC in the study population: rs111791349-A, rs15869-C, and c.*457-C (odds ratio (OR) range 3.7-15.4; p < 0.05). Genetic variants into the 3'UTR of BRCA1 and BRCA2 increased the risk of HBOC between 3.7-15.4 times in the study population. The presence/absence of these polymorphisms may influence the loss/creation of miRNA binding sites, such as hsa-miR-1248 in BRCA1 3'UTR or the hsa-miR-548 family binding site in BRCA2. Our results add new evidence of miRNA participation in the pathogenesis of HBOC.

Clinical stage I synchronous bilateral testicular germ cell tumor with different histopathology: a case report.

Bilateral testicular germ cell tumors (BTGCT) occur in 1 to 4% of patients with testicular cancer and of these, 10-15% are synchronous. Overall, BTGCT represents less than 0.5% of all new cases of testicular cancer. There are few reports in the literature of synchronous BTGCT with different histology. We present the case of a 30-year-old man who presented to our genitourinary tumor unit with a bilateral increase of testicular volume. After initial assessment, a testicular ultrasound showed the presence of solid tumors in both testes. Staging studies were negative for metastatic disease. The patient was referred to the fertility clinic for sperm banking and later underwent a bilateral radical orchiectomy. The histopathology evaluation revealed a 5.5 cm right-sided mixed germ cell tumor and a 1.5 cm left-sided testicular seminoma. Because patient's poor compliance for surveillance was identified as a risk factor for relapse and poor outcome, adjuvant chemotherapy was favored. The patient underwent one cycle of bleomycin, etoposide and cisplatin (BEP). After four years of follow up, the patient shows no evidence of relapse, either clinically or radiologically. In men unlikely to carry out successful surveillance; active treatment is the preferred option for preventing disease recurrence, even in patients with no risk factors. The physician must consider all available therapeutic measures in this scenario to achieve the best possible therapeutic result.

Analysis of the pathogenic variants of BRCA1 and BRCA2 using next-generation sequencing in women with familial breast cancer: a case-control study.

BACKGROUND: Pathogenic variants (PVs) of BRCA genes entail a lifetime risk of developing breast cancer in 50-85% of carriers. Their prevalence in different populations has been previously reported. However, there is scarce information regarding the most common PVs of these genes in Latin-Americans. This study identified BRCA1 and BRCA2 PV frequency in a high-risk female population from Northeastern Mexico and determined the association of these mutations with the patients' clinical and pathological characteristics. METHODS: Women were divided into three groups: aged ≤ 40 years at diagnosis and/or risk factors for hereditary breast cancer (n = 101), aged > 50 years with sporadic breast cancer (n = 22), and healthy women (n = 72). Their DNA was obtained from peripheral blood samples and the variants were examined by next-generation sequencing with Ion AmpliSeq BRCA1 and BRCA2 Panel using next-generation sequencing. RESULTS: PVs were detected in 13.8% group 1 patients (BRCA1, 12 patients; BRCA2, 2 patients). Only two patients in group 2 and none in group 3 exhibited BRCA1 PVs. Variants of uncertain significance were reported in 15.8% patients (n = 16). In group 1, patients with the triple-negative subtype, PV frequency was 40% (12/30). Breast cancer prevalence in young women examined in this study was higher than that reported by the National Cancer Institute Surveillance, Epidemiology (15.5% vs. 5.5%, respectively). CONCLUSIONS: The detected BRCA1 and BRCA2 PV frequency was similar to that reported in other populations. Our results indicate that clinical data should be evaluated before genetic testing and highly recommend genetic testing in patients with the triple-negative subtype and other clinical aspects.