Angelina Jolie has recently undergone a double mastectomy (as reported in this article) as a preventative measure. The actress has a family history of breast cancer and her mother died at an early age of 56 after battling breast cancer for a decade. She carries a defective version of the gene BRCA1, a DNA repair enzyme.

BRCA1 acts to repair double-strand DNA breaks through homologous recombination with intact DNA from the homologous chromosome, sister chromatid or within the same chromosome. Women who carry a mutation to BRCA1 are at greater risk of developing ovarian and breast cancer. In the article, she states:

My doctors estimated that I had an 87 percent risk of breast cancer and a 50 percent risk of ovarian cancer, although the risk is different in the case of each woman.
Only a fraction of breast cancers result from an inherited gene mutation. Those with a defect in BRCA1 have a 65 percent risk of getting it, on average.

Only a fraction of breast cancers result from an inherited gene mutation. Those with a defect in BRCA1 have a 65 percent risk of getting it, on average.

She goes on to indicate the hurdles genetic screening:

Breast cancer alone kills some 458,000 people each year, according to the World Health Organization, mainly in low- and middle-income countries. It has got to be a priority to ensure that more women can access gene testing and lifesaving preventive treatment, whatever their means and background, wherever they live. The cost of testing for BRCA1 and BRCA2, at more than $3,000 in the United States, remains an obstacle for many women.