Abstract 2558: A retrospective analysis of the spectrum of genetic variations associated with hereditary cancers in Indians

Abstract

Abstract The hereditary cancer burden in India is on the rise due to an increase in awareness of the disease, decrease in the cost of genetic testing and opportunities for genetic counseling. More and more individuals from high risk families are undergoing genetic testing to assess their likelihood of developing the disease. On the other hand, the clinical community is facing a significant challenge on how to interpret and classify a variant as disease-causing or benign. This is because a large fraction of the variants identified in the affected individuals from India have not been reported in hereditary disease databases such as the Breast cancer Information Core (BIC), Clinvar and Swissvar. These variants of unknown significance (VUS) present in individuals from high risk families create a great deal of uncertainty on clinical follow up and disease management. We performed a retrospective analysis on more than 300 affected cases of hereditary ovarian and breast cancer tested at our genomics center in the last three years. We compiled all the known pathogenic variants and compared their distribution in the Indian cohort with what has been reported worldwide. The most prevalent mutation in BRCA1 p.Glu23Valfs*17 (185delAG) was detected at a frequency of 20.34% in line with what has been found worldwide. In addition, frameshift mutations in BRCA1 and BRCA2 were most frequently detected in breast and ovarian cancer in line with previous findings. Additionally, our analysis identified 13 novel previously unreported and potentially pathogenic variants in BRCA1 and BRCA2 genes. Variants were also detected in several moderate penetrance genes such as CHEK2, BARD1 and ATM involved in DNA damage response and in MSH2 and MSH6 genes regulating epigenetic control through chromatin modification. In this study, we report novel pathogenic variants in genes associated with hereditary breast and ovarian cancer in the Indian population. Citation Format: Lakshmi Mahadevan, Aditya Nair, Vedam L. Ramprasad. A retrospective analysis of the spectrum of genetic variations associated with hereditary cancers in Indians. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2558.