BRCA1 and BRCA2 genes mutations among high risk breast cancer patients in Jordan

Abstract

Familial breast cancer is estimated to account for 15-20% of all cases of breast cancer. Surveillance for familial breast cancer is well-established world-wide. However, this service does not exist in Jordan, due to the scarcity of information with regard to the genetic profiling of these patients, and therefore lack of recommendations for policy-makers. As such, patients with very strong family history of breast or ovarian cancers are not screened routinely; leading to preventable delay in diagnosis. Whole coding sequencing for BCRA1/BCRA2 using next-generation sequencing (NGS)/Ion PGM System was performed. Sanger sequencing were then used to confirm the pathogenic variants detected by NGS. In this study, 192 breast cancer patients (and 8 ovarian cancer cases) were included. The prevalence of recurrent pathogenic mutations was 14.5%, while the prevalence of newly detected mutations was 3.5%. Two novel pathogenic mutations were identified in BRCA2 genes. The common mutations in the Ashkenazi population used for screening may not apply in the Jordanian population, as previously reported mutations were not prevalent, and other new mutations were identified. These data will aid to establish a specific screening test for BRCA 1/BRCA2 in the Jordanian population.

Figure 1

BRCA1 and BRCA2 variants versus inclusion criteria. Top BRCA1 patients, middle BRCA2 patients and bottom BRCA1 and BRCA2 patients. Criteria code combined: 1: Female breast cancer patients younger than the age of 35, 2: At least the following female breast cancers only in the family, 3: Families containing one relative with ovarian cancer at any age and, on the same side of the family, 4: Families affected by bilateral cancer (each breast cancer has the same count value as one relative, 5: Families containing male breast cancer at any age and, on the same side of the family.

Figure 2

Schematic diagram of BRCA1 and BRCA2 proteins with the position of all identified pathogenic variants. Novel variants are marked with a caret (^).