Validation of BRCA mutation-carrier probability model, BRCAPRO, in Japanese.

Abstract

e12532 Background: Genetic testing has not been widely performed in Japan. It is not known whether BRCA mutation-carrier model is useful for selecting eligible person of genetic testing. We studied the validation of BRCAPRO in Japanese. Methods: Twenty-six hundred sixty-five people visited to our hospital between 2011 and 2012.They were surveyed family history as a risk factor of inheriting breast cancer according to NCCN guideline. Among them, those who have a number of family history of breast cancer, ovarian cancer, pancreatic cancer, prostate cancer were selected and in addition, genetic counselor constructed family tree. We also calculated BRCA1/2 mutation probability by BRCAPRO.Those who had more than 10% mutation probability and early onset breast cancer, triple negative breast cancer were received genetic counseling and genetic testing for applicants. We also calculated sensitivity, specificity and predictive value at 10% estimated probability. Results: One hundred five people (3.9%) were selected as a risk of inheriting breast cancer, of which sixty-three people (2.3%) were constructed family tree.The number of people who had more than 10% and 30% mutation probability by BRCAPRO was seven (0.26%) and three (0.11%).Nine people performed BRCA1/2 genetic testing (proband : eight, relative: one)Four people carried a deleterious BRCA mutation (BRCA1: three, BRCA2: one).In the cases which had more than 30% mutation probability, all of them carried a deleterious BRCA mutation. Most of their mutation site was L63X which was most frequent in Japan. Using a 10% cut-off, sensitivity was 75%, specificity was 80%,positive predictive value was 75%. When it comes to the cases which had more than 30% mutation probability, Sensitivity, specificity, positive predictive value were all 100%. Conclusions: Our findings suggest BRCAPRO is useful in Japanese, especially those who have more than 30% mutation probability.