Molecular 'clock' could predict risk for developing bre...(st. A computer program developed by...)

A computer program developed by Dr. Euhus was used to determine the breast-cancer risk for patients in the study. Dr. Euhus has written several interactive software tools for risk measurement, which are used by major cancer centers worldwide.

His findings indicate that methylation of RASSF1A and other genes increases steadily during the years of ovarian cycling up to about age 55 suggesting that methylation is, indeed, a molecular clock recording the history of cell divisions.

Interestingly, having children, which is known to reduce breast-cancer risk if it occurs early in life, was associated with a reduction in methylation for some genes, Dr. Euhus said.

Dr. Euhus says the clock is not always marching forward, and there are ways to turn it back.

Methylation can be stopped or slowed down, said Dr. Euhus, who also directs the Mary L. Brown Breast Cancer Genetics and Risk Assessment Program at the Harold C. Simmons Comprehensive Cancer Center. We found that having a baby set the clock backward and so did getting close to menopause. Things that are known to reduce breast-cancer risk may also turn the clock backward.

A test for methylation of tumor-suppressor genes is not commercially available and Dr. Euhus says additional research is necessary to fully understand the mechanism. For example, it is not clear whether tumor-suppressor gene methylation is simply a marker of prior cell divisions, or whether it can cause increased cell division, hastening the development of breast cancer.

Dr. Euhus said medications that interfere with methylation might provide a new approach for reducing breast-cancer risk.

Even if theres a lot of methylation, I cant tell for sure if a woman is going to develop breast cancer, Dr. Euhus said. However, if I took two women from our study and one had more methylation than the other, the one with more methylation was more likely to have already had breast biopsies fo
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