BRCA 1 and BRCA 2 mutations in Saudi breast cancer patients (single institution).

Abstract

10 Background: Breast cancer is the commonest malignancy among Saudi females accounting for 25% of all female cancers with a median age at diagnosis of 47 years (1,2). In Saudi, breast cancer showed an increased incidence attributed to many factors such as different lifestyles, reproductive pattern, family history, which was reported to account for 59%, dietary or cultural practice of Saudi women (2,3,4,5). The multifunctional and highly penetrant BRCA 1 and BRCA 2 are the two major breast cancer pre-disposition genes, accounting for about 20% of breast cancer families (6,7). To our knowledge, the prevalence of BRCA 1 and BRCA 2 mutations in native Saudi population is sparse (8,9). Our aim is to describe the findings of BRCA mutation testing in native Saudi patients with breast cancer in a large Ministry of National Guard Health Affairs (NGHA) community-based teaching hospital. Methods: In this study, 75 out of 516 patients with breast cancer who were clinically and histopathologically diagnosed at NGHA from October 2010 to April 2014 were included. Selection criteria: aged ≤ 40 years bilateral breast cancer, triple-negative breast cancer, strongly first degree family history at young age and male breast cancer. Molecular alterations were performed by direct gene sequencing, multiple ligation – dependent probe amplification (MLPA) at Bioscentia human genetic testing in Germany. Results: 75 native Saudi were enrolled and test performed for them. 18 patients (24%) were found to have mutation of which 10 in BRCA One and six in BRCA 2. Two have both BRCA 1 and BRCA 2. Seven patients have the same with deleterious mutations in BRCA 1 gene. Two of them are mother and daughter and other five are unrelated. The mean age of breast cancer diagnosis in the mutation carriers was 38 years. Triple negative breast cancer (TNBC) diagnosed in six patients, bilateral breast cancer diagnosed in one, first-degree family history in eight and second degree in 10 patients and four with no family history. Conclusions: BRCA 1 and BRCA 2 mutations are an important contributor to the etiology of breast cancer in Saudi women. A mutation in BRCA 1, C 1648 > C p, Asn550His in exon 10 has been reported as disease causing (11) and it is found in our study in seven patients. Such mutation might be specific for Saudi, so further studies are highly recommended.