Antidote: On DNA testing for cancer

Marc Siegel, MD
Marc Siegel, MD

We are reaching an exciting new time in medicine when genetics will play a major role in predicting and treating disease. We already use a drug known as Herceptin to treat breast cancer victims with a mutation of the HER2 gene. But this is only the beginning. With several malignancies, including breast and prostate, scientists are in the process of identifying specific genes where abnormal expression leads to an increased risk of aggressive tumors.

In the future, these genetic abnormalities will be identified and patients will know their risks a lot better than they do right now. In addition, patients will know how aggressive a cancer is based on its genetic makeup. This will lead to smarter surgical decisions. Patients who are higher risk may undergo surgery because the cancer is known to be a more aggressive type. Or they may choose to forego surgery because the tumor is known to be the kind that doesn't spread.

It also won't be long before we have an arsenal of genetic treatments to offer patients with cancer and to offer family members at high risk before they ever get cancer.

Scientists are beginning to identify genes whose mutations are common to more than one type of cancer. Many people have heard of BRCA 1 and 2, which are associated with aggressive breast, ovarian and prostate cancers. Mutations of the ATM, CHEK2, and PALB2 genes have been associated with both aggressive breast and prostate cancers.

A recent study from the Institute of Cancer Research in London identified 14 separate mutations which greatly increased the odds of aggressive prostate cancers. In fact, the results of the study, published in the British Journal of Cancer, revealed that 7% of the men with prostate cancer had the 14 high-risk mutations and the kind of aggressive prostate cancer that spread easily.

In the very near future, men will go to the doctor's office for a battery of genetic tests which predict their future risks of cancer, along with what to do beforehand as well as what treatment to get if that dreaded diagnosis comes.