A novel method to detect the Mexican founder mutation BRCA1 ex9‑12del associated with breast and ovarian cancer using quantitative polymerase chain reaction and TaqMan� probes

Abstract

In 2015, according to the National Institute of Statistics and Geography (INEGI), malignant breast tumors were the first cause of cancer fatality in women (6,273 fatalities) in Mexico, whereas 2,793 fatalities in women were due to ovarian cancer. A total of 5–10% of breast cancer and 10–15% of ovarian cancer cases are caused by a hereditary breast-ovarian cancer syndrome, with mutations predominantly identified in the BRCA1 and BRCA2 genes. Recently, the Mexican founder mutation BRCA1 ex9-12del was identified (deletion of exons 9–12 with recombination between introns 8–12). This is the most frequently reported mutation in hereditary breast/ovarian cancer in Mexico. Current detection methods include end-point polymerase chain reaction (PCR) and Multiplex Ligation-dependent Probe Amplification (MLPA). In the present study a cheap, sensitive and fast detection method was developed based on quantitative PCR and two TaqMan® probes, one to detect the deletion (recombination region between introns 8 and 12), and the other one a region from exon 11. With this assay, 90 samples were able to be analyzed in 2 h using 2.5 ng of DNA/reaction at a cost of ~2–3 USD. This method is capable of detecting positive samples for DNA deletion and excluding negative ones. Therefore, the method proposed may be a useful high-throughput diagnostic option that could be useful in future association or prevalence studies that use large populations.

Clinical Benefits of Olaparib in Mexican Ovarian Cancer Patients With Founder Mutation BRCA1-Del ex9-12

“…In Mexico, mutation screening in OC patients with and without cancer family history is limited ( Martínez-Treviño et al, 2018 ). Very few research and medical oncology care centers provide this multidisciplinary care service, which allows the identification of patients that may benefit from new therapies for treatment with PARPi ( Fragoso-Ontiveros et al, 2019 ).…”

Personalized Medicine in Ovarian Cancer: A Perspective From Mexico

“…Regarding efforts to bring the promise of PM to OC Mexican patients, key milestones are: 1) The description of the first Mexican founder BRCA1 mutation, ex9-12del, germline deletion of exons 9-12 [ 31 ]; 2) The formulation of an anti-angiopoietin therapy with trebananib for recurrent OC [ 32 ]; 3) The detection of BRCAs mutations in 28% (26/92) of a cohort of OC cases in 2015 [ 22 ]; 4) The development of a simple and low-cost screening method for the Mexican founder mutation ( BRCA1 ex9-12del) based on quantitative polymerase chain reaction (qPCR) [ 33 ]; 5) The role of microRNAs in its angiogenesis [ 34 ]; 6) The characterization of let-7d-3p in the apoptosis and sensitization to chemotherapy in OC cells [ 35 ]; 7) The identification of the proteomic profile of ascites in epithelial OC [ 36 ]; 8) The identification of 76 polymorphic variants in northeast Mexican patients with sporadic OC (50 of those variants were not previously reported) [ 26 ]; 8) The discovery of molecular components involved in OC pathogenesis, such as the hypoxia-regulated miRNAs (HypoxamiRs) Profiling Identify, that identified the miR-765 as a regulator of the early stages of tumor vasculogenesis [ 37 ] to mention one.…”