What is this BRCA business?

I forget that BRCA isn't part of everyone's normal vocabulary, like it is for me.  Here are some random explanations/stats on BRCA and hereditary cancer.  More later.

 BRCA1 and BRCA2 are human genes that belong to a class  of genes known as tumor suppressors.   In normal cells, BRCA1 and BRCA2 help ensure the stability  of the cell’s genetic material (DNA) and help prevent uncontrolled cell  growth. Mutation of these genes has been linked to the development of hereditary  breast and ovarian cancer.  The names BRCA1 and BRCA2 stand for breast  cancer susceptibility gene 1  and breast cancer susceptibility  gene 2, respectively.

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Most cases of cancer are considered “sporadic” and their cause is unknown.  About 10% of many cancers—including breast and ovarian cancer—are considered hereditary. BRCA mutations can happen in any population, and mutations have been found in families of all ethnicities. People of certain heritages are more likely to carry BRCA mutations, but families of any ethnic background can carry a mutation.

Experts estimate that, in the general population, one in every 300 to 500 people harbors a BRCA mutation. BRCA mutations are more common in people of Eastern European (Ashkenazi) Jewish descent.  It is estimated that one in every 40 people of Eastern European Jewish descent (2.5% of this population) carries a BRCA mutation. Members of certain other ethnic groups may also be more likely than those in the general population to carry a BRCA mutation.  However, it is important to remember that any family can have a BRCA mutation, regardless of its ethnic background. 

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Certain variations of the BRCA1 gene lead to an increased risk for breast cancer . Researchers have identified hundreds of mutations in the BRCA1 gene, many of which are associated with an increased risk of cancer. Women who have an abnormal BRCA1 or BRCA2 gene have up to an 85% risk of developing breast cancer by age 70; increased risk of developing ovarian cancer is about 55% for women with BRCA1 mutations and about 25% for women with BRCA2 mutations.