Previous studies have found that PRDM1 is involved in a variety of fundamental cellular processes, including proliferation, differentiation and apoptosis-which can all go awry in cancer. The gene's activity is lost in many cancer types.

In Onel's small samples, only three percent of patients with both of the protective variants developed second cancers within 30 years; nearly 33 percent of those with both of the high-risk variations did.

"Taken together," the authors note, "our findings support a novel role for PRDM1 as a radiation-responsive tumor suppressor." PRMD1 may be important for understanding the causes of second cancers in survivors of pediatric Hodgkin's lymphoma as well as in other cancer patients treated with radiation therapy."

This study should also "bring some optimism" back to genome-wide association studies, Onel added. Most previous cancer-related markers found through GWAS have been "of little clinical value for predicting risk, response to therapy or survival." But by incorporating environmental exposure, such as radiation therapy, into genomic investigations, "much of the missing heritability can be revealed," he said. "By folding in the environmental component, we were able to ask a more targeted question. This approach could improve our ability to integrate genomics into routine cancer care."

Source: University of Chicago Medical Center