JeneScreen BRCA testing program (Sydney)

How do gene faults cause cancer?

Have you ever wondered how our skin starts growing after we cut ourselves and then miraculously stop growing once it has healed? The answer lies in our genes. Our genes are recipes for proteins which control our cells. Some of these proteins are the triggers for our cells to divide and grow, as well as the brakes which regulate that growth.

If a cell develops mistakes in these growth regulating genes, a cancer may develop. Although such mistakes occur often, particularly as we get older, cancer is usually prevented by other genes which detect and repair such mistakes. Only when all the repair genes in that cell break down does a cancer actually occur.

Sometimes a person inherits a faulty repair gene which means that they are already missing one safeguard against cancer. Most repair genes are important for protecting us against certain types of cancer, so an inherited faulty repair gene increases the risk of getting only certain types of cancer.

We all carry BRCA1 and BRCA2 genes. Their main function is to protect women against breast and ovarian cancer. BRCA2 also protects men against prostate cancer.

We all carry 2 copies of BRCA1 and of BRCA2 - one inherited from our mother and one from our father. We only need to inherit one faulty copy to increase our risk of getting cancer, and to make us more likely to develop cancer at a younger age than average.

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