International Journal of Hematology and Oncology 2024, Vol 34, Num 1 Page(s): 044-049
New Perspectives on the Recurrent BRCA Mutations and Clinical Variability

Ibrahim SAHIN1, Hanife SAAT1, Sercan AKSOY2

1University of Health Sciences, Dışkapı Yıldırım Beyazıt Training and Research Hospital, Department of Medical Genetics, Ankara, TURKEY
2Hacettepe University, Faculty of Medicine, Department of Medical Oncology, Ankara, TURKEY

Keywords: Hereditary breast and ovarian cancer syndrome, Lynch Syndrome, BRCA1, BRCA2
Familial cancer syndromes include about 5% to 10% of all tumors and are attributable to genetic defects. Hereditary breast and ovarian cancer syndrome (HBOC) is distinguished by an elevated risk for male and female breast cancer, ovarian cancer (Fallopian tube and primary peritoneal cancers), and to a smaller degree, other cancers such as prostate cancer, pancreatic cancer, and melanoma. In this study, we performed next-generation sequencing or a comprehensive cancer panel on 335 patients to explain the importance of recurrent germline mutations of BRCA1-2 and their clinical results and determine how often BRCA gene mutations were seen in people suspected of Lynch syndrome. BRCA2 mutations were more predominant (n= 212, 63.3%) than BRCA1 mutations (123, 36.7%) in all groups except for the ovarian and breast-ovarian groups. The most common recurrent mutations were BRCA2:c.3318C>G, BRCA2:c.632-2A > C, BRCA1:c.5266dupC, BRCA2:c.9317G > A, BRCA2:c.8452G > A, BRCA1:c.2800C > T, respectively. BRCA1 variants were associated with ovarian cancers, and BRCA2 variants show a higher incidence of extra-ovarian malignancy. The principal finding of our study is that BRCA2 mutations were more predominant not just in the breast group but also in the colorectal group. This is the first study mentioning the importance of BRCA2 variants in patients with Lynch Syndrome (LS) phenotype to the best of our knowledge. Our data broadens the spectrum of BRCA gene mutations and provides insights for genotype-phenotype correlations for familial cancer syndromes.