Prevalence of BRCA1 and BRCA2 germline variants in an unselected pancreatic cancer patient cohort in Pakistan

Abstract

Background: BRCA1 and BRCA2 (BRCA1/2) are the most frequently investigated genes among Caucasian pancreatic cancer patients, whereas limited reports are available among Asians. We aimed to investigate the prevalence of BRCA1/2 germline variants in Pakistani pancreatic cancer patients. Methods: One hundred and fifty unselected and prospectively enrolled pancreatic cancer patients were comprehensively screened for BRCA1/2 germline variants using denaturing high-performance liquid chromatography and high-resolution melting analyses, followed by DNA sequencing of the variant fragments. The novel variants were analyzed for their pathogenic effect using in-silico tools. Potentially functional variants were further screened in 200 cancer-free controls. Results: Protein truncating variant was detected in BRCA2 only, with a prevalence of 0.7% (1/150). A frameshift BRCA2 variant (p.Asp946Ilefs*14) was identified in a 71-year-old male patient of Pathan ethnicity, with a family history of abdominal cancer. Additionally, we found a novel variant in BRCA2 (p.Glu2650Gln), two previously reported variants in BRCA1 (p.Thr293Ser) and BRCA2 (p.Ile2296Leu) and a recurrent nonsense variant in BRCA2 (p.Lys3326Ter). These variants were classified as variants of uncertain significance (VUS). It is noteworthy that none of these VUS carriers had a family history of pancreatic or other cancers. Conclusions: In this first study, BRCA1/2 pathogenic variant is identified with a low frequency in pancreatic cancer patients from Pakistan. Comprehensive multigene panel testing is recommended in the Pakistani pancreatic cancer patients to enhance genetic understanding in this population.