Breast and Ovarian Cancers
Gene changes and the risk of Breast and Ovarian Cancer
Most cases of breast and ovarian cancer happen by chance and are not caused by an inherited mutated gene. For assessing the risk of sporadic (non-familial) breast cancer, there is the BREVAGen test. By combining both clinical risk factors with an individual’s genetic markers, BREVAGen provides a 5 year and lifetime percentage risk of developing breast cancer.
However, when several members of a family have developed the same type of cancer, or when individuals develop cancer at an unusually young age (less than 50), it is natural to question whether an inherited factor is involved. About 5% of women with breast cancer have the BRCA gene mutation. Having a mutation of the BRCA1 or BRCA2 gene increases the risk of breast cancer far more than does any other known risk factor for this disease.
According to estimates of lifetime risk, about 12 percent of women (120 out of 1,000) in the general population will develop breast cancer sometime during their lives compared with about 60 percent of women (600 out of 1,000) who have inherited a harmful mutation in BRCA1 or BRCA2.
In other words, a woman who has inherited a harmful mutation in BRCA1 or BRCA2 is about five times more likely to develop breast cancer than a woman who does not have such a mutation.
Lifetime risk estimates for ovarian cancer among women in the general population indicate that 1.4 percent (14 out of 1,000) will be diagnosed with ovarian cancer compared with 15 to 40 percent of women (150–400 out of 1,000) who have a harmful BRCA1 or BRCA2 mutation.
Testing should be offered to women who have a high likelihood of having a mutation of the BRCA1 or BRCA2 gene.... read more