The importance of variants of unknown significance (VUS) in BRCA mutation.

Abstract

e22507 Background: Genetic testing of patients for BRCA mutation may report variants of unknown significance (VUS). The use of multi-gene panels in clinical care has been increasing. Consequently, the reporting of variants of unknown significance has also increased. More than two decades of research and testing have elevated the status of BRCA1 and BRCA2 genes as the most well characterized genes. However, VUS are found even in BRCA1/2 testing. This raises many ethical and policy issues including communicating the significance of the results and possible clinical management options to patients. The practicing physicians would face the ethical and potential legal burden of contacting and explaining to patients, when any role of VUS changes and gets reclassified as potentially harmful. Methods: Data were collected retrospectively from medical records of patients tested for BRCA mutations. The results of fifty-two patients were analyzed. Eight patients had BRCA1 and BRCA2 mutations and twelve patients had variants of unknown significance. Results: When the results of thirteen patients with BRCA mutations with VUS were analyzed further, the variants included POLE, CHEK2, PALB2, MUTHYH, BR1P1, MSH3, ATM, RAD51C, GALNT12, etc. The age of these patients ranged from 39 years to 69 years. Four patients had ovarian cancer and eight patients had breast cancer, and one patient had both breast and ovarian cancers. The number of patients with stage IV, III, II, and I diseases were six, one, two, and two respectively. One patient had bilateral breast cancer and one patient had carcinoma in-situ. Eight patients had family histories of various cancers, including cancers of the breast, uterine, and prostate cancer. All patients were treated appropriately and three patients died due to their disease. Conclusions: Based on patients’ age, family histories, and disease characteristics BRCA mutation analyses were done. All patients tested positive for BRCA mutations and VUS were informed about their results. Variants of BRCA1 and BRCA2 occur in 2%-4% of tests depending on the laboratories, where the tests were performed. There is no concordance as to how VUS results were reported. There is conflicting evidence regarding the pathogenicity of VUS. These make clinical recommendations very complex. Based on existing guidelines, physicians can explain the details of the significance of BRCA! And BRCA2 mutations to patients with clarity. However, it is difficult and unclear to give recommendations regarding prophylactic measures, specific treatment options for BRCA mutation positive breast and ovarian cancer, follow-ups, and family testing in patients with VUS. Therefore, during BRCA testing, when VUS are reported routinely along with mutations of known significance, the treating physicians would need a better guidance to advise their patients without unduly increasing their anxiety, fear, and potential for misunderstanding.