Predictors and prevalence of germ-line BRCA mutations in high-risk patients among different ethnicities.

Abstract

190 Background: Germ-line mutations in tumor suppressor genes, BRCA1 and BRCA2, confer high risks of breast and ovarian cancer in affected individuals. Genetic testing for these pathogenic mutations has potentially important health implications for judicious counseling and screening of high risk individuals. Methods: A retrospective analysis was conducted of all the patients seen at our oncology/genetics clinic from 2000 to 2010. A population of over 500 patients was identified, out of whom 310 subjects underwent risk factor assessment. BRCA testing was performed on 231 of these subjects whereas 79 subjects were not tested secondary to lack of insurance/follow up, or patient/physician preference. Various ethnic groups were identified which included 138 Caucasian, 41 African American, 28 Ashkenazi Jewish, 4 Middle Eastern, 2 Asian and 2 Hispanic subjects. The ethnicity of 16 subjects was unknown secondary to lack of documentation. Results: BRCA mutation testing was completed on 231 subjects out of whom 34 were identified as carriers, comprising 31 female and 3 male individuals. 25 subjects carried BRCA1 and 11 subjects carried BRCA2 mutations, whereas 2 subjects carried both mutations simultaneously. In terms of racial prevalence, the population screened was divided into 4 main groups. Using the Maximum Likelihood Ratio Chi-Square Test, a p-value of 0.96 (p=0.9633) was obtained which indicated that the proportion of mutation did not differ for the races among the population screened. Conclusions: The estimated ethnicity prevalence of BRCA mutations was found to be the highest in African American followed by Caucasian and Ashkenazi Jewish subjects in the population screened at our facility. Overall, BRCA mutations are more common in the Jewish population on which most of the research has been focused. Our study is one of the few to indicate the possibility of high prevalence of mutations in the under-studied and less reported high risk kindred, that is, the African Americans. [Table: see text]