13q12-13 chromosome disorder.
Mutations are usually insertions or deletions of a small number of DNA base pairs in the gene.
The only known function of BRCA2 is to help initiate homologous recombination.
Defects in the BRCA2 protein makes it unable to repair mutations that occur in other genes resulting in mutation build up and causing cells to divide in an uncontrolled way.
Women with BRCA2 mutations have a 12-23 % lifetime risk of developing ovarian cancer.
By age 80 BRCA2 carriers have a 12-17% cumulative risk of developing ovarian cancer.
BRCA2 carriers have a lower penetrance for ovarian cancer then do BRCA1 carriers.
Carriers of BRCA2 mutation with ovarian cancer have improved overall survival and response rate to chemotherapy compared with BRCA wild-type mutation: Five-year overall survival with 60% for BRCA2 versus 25% for carriers of wild-type BRCA or BRCA1 mutations.
Prophylactic oophorectomy following diagnosis of breast cancer among women with BRCA1 or BRCA2 mutation reduces the risk of dying of breast cancer: In a study of 676 women with the above mutations 345 underwent bilateral oophorectomy the adjusted hazard ratio was 0.38 for BRCA1 carriers. and 0.57 for BRCA2 carriers. (Metcalfe K et al).
Among BRCA2 carriers the cumulative risk of developing breast cancer by age 80 is 66-69%.
In BRCA 2 carriers 16% of tumors are triple negative and most 77% express their estrogen receptor.
BRCA2 is associated with melanoma
The risk of breast cancer in men is significantly increased in BRCA2 mutation carriers.
The risk of breast cancer in men with BRCA2Â mutations is 7-14%.