BRCA1 and BRCA2 truncating mutations and variants of unknown significance in Egyptian female breast cancer patients

Abstract

Background: Breast cancer is the most common malignancy among women worldwide and the leading cause of cancer death in economically developing countries. We sought to study the contribution of BRCA1/2 mutations to the burden of breast cancer in Egypt.

Patients and methods: 103 Egyptian female breast cancer patients, unselected for age of onset or family history, were included in the study. Mutational screening of some exons of BRCA1/2 genes was performed using High Resolution Melting analysis followed by direct sequencing of detected variants.

Results: Twenty sequence variants were identified. According to the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG/AMP) guidelines, 8 variants were classified as pathogenic (Class 5), 1 as likely pathogenic and 11 as variants of unknown significance (Class 3). The pathogenic variants comprised 5 novel frameshift mutations; BRCA1 c.5205delA and BRCA2 (c.3641delT, c.3291dupT, c.3292delA, and c.787dupA) mutations; 1 novel nonsense mutation (BRCA2 c.3280A>T) and 2 previously described missense mutations (BRCA1 c.117T>G, c.110C>A).

Conclusion: This study provides the results of our attempt to delineate the genetic aspect of breast cancer among the Egyptian population and emphasizes the necessity of implementing screening strategies for early diagnosis and counseling for breast cancer in Egypt.

Keywords: ACMG/AMG; BRCA1; BRCA2; Bioinformatics; Breast cancer; Egypt; HRM; Pathogenic mutations; Variants of unknown significance.