Gene Variations Can Predict Radiation-Induced Toxicity Risk

Key genetic variants may affect how cancer patients respond to radiation treatments, according to new research. Scientists discovered that differences in the TANC1 (tetratricopeptide repeat, ankyrin repeat and coiled-coil containing 1) gene are associated with a greater risk for radiation-fueled side effects in prostate cancer patients, which include impotence, diarrhea, and incontinence.

These findings, published July 2014 in Nature Genetics, are based on a genome-wide association study, a type of study in which researchers studied a variety of genetic variants to see if any of them are tied to a specific type of complication, which could sometimes appear years after treatment was completed.

“Our findings, which were replicated in two additional patient groups, represent a significant step towards developing personalized treatment plans for prostate cancer patients,” said Barry S. Rosenstein, PhD, professor, radiation oncology, genetics and genomic sciences, Icahn School of Medicine at Mount Sinai (New York, NY, USA), the lead Mount Sinai investigator on the study. “Within five years, through the use of a predictive genomic test that will be created using the data obtained in the recent study, it may be possible to optimize treatment for a large number of cancer patients.”

For the study, Dr. Rosenstein and his colleagues obtained blood samples from nearly 400 patients who were receiving radiotherapy treatment for prostate cancer. The blood samples were screened for roughly one million genetic markers, and each patient was monitored for at least two years to monitor incidents of side effects from the radiation. Data analysis revealed which genetic markers were consistently associated with the development of complications following radiotherapy.

“The next step is to validate the results, and see if the same markers predict similar outcomes in patients with other forms of cancer,” said Dr. Rosenstein. Using the genomic test being developed, treatment plans can be adjusted to curtail adverse effects thereby allowing for an improved quality life for many cancer survivors.

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Icahn School of Medicine at Mount Sinai