The innate capacity to repair damaged DNA seems to affect a woman’s chance of developing breast cancer. Deficient DNA repair appears to triple the risk of breast cancer, researchers have found.

“A lot of studies have looked at the link between DNA repair capacity and lung cancer risk, but few studies have evaluated the association with breast cancer risk,” Dr. Regina M. Santella, from Columbia University in New York, told AMN Health.

Santella’s group used various lab techniques to compare the DNA repair capacity of cells obtained from 158 women with breast cancer and from their sisters who didn’t have cancer.

The average percentage of damaged DNA that could be repaired was significantly lower in the breast cancer patients than in their unaffected siblings, the investigators report in the Journal of the National Cancer Institute.

Moreover, as DNA repair capacity diminished, the risk of breast cancer rose, with about a 3-fold difference between those with the highest capacity versus those with the lowest.

Santella said these findings could have implications for breast cancer screening. “The ultimate goal is to understand an individual’s risk for cancer development so that you can better target screening and prevention efforts.”

She noted that the assay used in the present study looked at just one of many DNA repair mechanisms. “At this point, we’re interested in conducting a study using an assay that measures a different DNA repair pathway. Looking at the status of several different pathways may give a better estimate of breast cancer risk.”

In a related editorial, Dr. Marianne Berwick, from the University of New Mexico in Albuquerque, and Dr. Paolo Vineis, from Imperial College in London, point out that measuring DNA repair capacity is complicated at present. Once simple and rapid assays are available, it may be possible to develop “interventions to reduce cancer incidence and mortality.”

SOURCE: Journal of the National Cancer Institute, January 19, 2005.