Health Library

Genetic Signature Shows Risk for Cancer Recurrence

A genetic "signature" that consists of 186 genes combined together can predict the risk of recurrence for some common cancers, according to a report in the New England Journal of Medicine (NEJM).

A set of genes predicts the recurrence of breast cancer, prostate cancer, lung cancer, and medulloblastoma, the most common form of childhood brain cancer, the researchers found.

"This is very impressive data that will hopefully be able to predict which patients can benefit or not benefit from certain types of treatment," says Dr. Jay Brooks, at Ochsner Health System in Baton Rouge. "Whether this can be taken into the direct clinical arena will remain to be seen."

Genes Linked to Better Survival Rates

The authors of the study, from Stanford University and the University of Michigan, say they are already working to make the findings available to physicians and their patients.

A small number of cells within breast cancer are believed to be the ones that actually cause the cancer to grow. These "cancer stem cells" were first identified in 2003.

The researchers participating in the new study compared the gene expression profile of breast cancer stem cells with that of normal breast cells. From that data, the researchers culled a list of 186 genes that comprised an "invasiveness" gene signature.

This signature was then evaluated to see how it related to overall survival as well as metastasis-free (no cancer spread) survival in patients.

As it turned out, there was a strong correlation between the gene signature and both overall and metastasis-free survival, note the researchers.

The gene signature was then combined with prognostic criteria from the National Institutes of Health (NIH)  to classify patients into those with a "good" or "poor" prognosis.

Those with a good prognosis had a 10-year rate of metastasis-free survival of 81 percent, while those with a poor prognosis had a rate of 57 percent.

And when the gene signature was combined with a second group of genes previously identified by researchers, the signature's predictive value was even more accurate.

Dense Breasts Linked to Higher Risk

A second study reported in the same issue of the Journal found that denser breasts were associated with a higher risk of breast cancer.

The risk was elevated in cancers found both at screenings and in the period between screenings, according to Dr. Norman Boyd, at Princess Margaret Hospital in Toronto.

Women with breast density in 75 percent or more of their baseline mammogram had about a five times greater risk of breast cancer, compared with women who only had density in 10 percent of their first-ever mammogram.

The findings held true after adjusting for all known risk factors for the disease.

These findings confirm previous research, but they use more modern technology, says Dr. Boyd.

"We wanted to see whether we would see similar messages with modern mammography, and we did," he says. "We also wanted long-term observation.

"Women should understand that this [breast density] is indeed a risk factor with the same kind of awareness they might accept knowing that some of their relatives have breast cancer," notes Dr. Boyd.

"If they know they have dense breast [tissue] and something changes, they may report it more promptly," he says.

And women on hormone replacement therapy, which can increase breast density, should talk with their physician about what they should do, explains Dr. Boyd.

Always consult your physician for more information.