Analysis of Heterozygous BRCA1 5382ins Founder Mutation in a Cohort of Egyptian Breast Cancer Female Patients Using Pyrosequencing Technique

Abstract

Background: Up to half of the heritable mutations in breast cancer (BC) are attributed to BRCA1 and BRCA2 genes. The mutation prevalence is variable based on ethnicity and may be influenced by founder mutations. The aim of this pilot study is to determine for the first time, the prevalence of BRCA1 5382insC founder mutation in a cohort of Egyptian familial breast cancer patients (FBC).

Methods: Female patients were selected to have familial type of breast cancer. Twenty healthy females were included as a control group. Peripheral blood samples were withdrawn from all studied females and were analyzed for BRCA1 5382insC founder mutation detection using pyrosequencing technique.

Results: Eighty Egyptian FBC females were eligible to be enrolled in the study with a mean age of 48.31 ± 10.97years.We found a BRCA1 5382insC mutation carrier frequency of 5% of total studied FBC patients (4 out of 80 patients) with 95% confidence interval (1.61-12.99). There was a high statistical significant difference between carriers and non-carriers concerning the number of affected family members by BC, (p=0.001). Conclusion: BRCA1 5382insC founder mutation is not uncommon among Egyptian FBC females. The carrier frequency is comparable to that reported worldwide; however it is lower than those from previous Egyptian studies using different molecular techniques. The strong association between the mutation and the number of affected family members suggest wider screening of the mutation among high risk families using the reliable pyrosequencing technique.

Keywords: BRCA 1 mutation; Pyrosequencing technique; familial breast cancer.

Figure 1

Visualization of PCR Products on Gel Prior to Pyrosequencing. 50 bp Ladder (on the Left) and the Product Band at 72 bp for Seven Different Samples (on the Right).

Figure 2

Pyrograms Showing Heterozygous Insertion of C Indicated by an Arrow that is Present in the Mutant (2-b), but not in the Wild-Type (2-a) of BRCA1 5382insC. Pyrograms at positions 1 and 3 shows one unit G and one unit T (arrowheads) which are negative nucleotide dispensations that serve as internal controls for nucleotide misincorporation