ovarian cancer : BRCA1 and BRCA2: Their Function

Researchers used to think that the BRCA1 and BRCA2 genes were tumor suppressor genes. Although researchers are still trying to understand precisely how the two genes function, they now believe that they may actually be what are called mismatch repair genes. (For recent news about the role of BRCA2, see Related News below.)

To understand what's meant by this, you need to understand a little bit about the cell replication process that occurs constantly within our bodies. As our cells age and die, new cells must be made to replace them. For this to happen, each of the three billion letters of DNA that are found within every cell has to be copied — one letter at a time. Not surprisingly, mistakes sometimes occur. When this happens, a gene may stop making its protein or the the protein can cease to function normally.

To ensure that such mistakes don't accumulate, our body has special proteins — called mismatch repair proteins — that check for and then correct mistakes in the newly made DNA. The genes that produce these special proteins are called mismatch repair genes — and it is in two of these genes (BRCA1 and BRCA2) that researchers have discovered the mutations most commonly linked with breast and ovarian cancer.
When a person's mismatch repair genes aren't functioning properly, they may not be able to catch and correct those inevitable DNA copying mistakes. And when such mistakes occur in genes whose function it is to prevent a cell from becoming cancerous, malignancies can occur.

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