A protein that controls gene activity may help predict survival for colorectal cancer patients. The protein appears to be linked to the disease’s spread, as well.
|David Ann, left, and Yun Yen (Photo by Darrin S. Joy)|
First reported online Jan. 20 in Clinical Cancer Research, the findings one day could help physicians tailor treatment to specific patient needs.
City of Hope scientists collaborated with researchers from Second Affiliated Hospital, Zhejiang University School of Medicine in Hangzhou, China, on the study, which found that levels of a protein called HMGA2 — short for high mobility group A2 — strongly corresponded to how well colorectal cancer patients fared.
“We found that higher expression of HMGA2 strongly correlated with lower survival,” said Yun Yen, M.D., Ph.D., Dr. & Mrs. Allen Y. Chao Chair in Developmental Cancer Therapeutics and chair of the Department of Molecular Pharmacology at City of Hope. Yen shared senior authorship on the study with David Ann, Ph.D., professor of molecular pharmacology.
Testing tumor samples taken from 280 colorectal cancer patients, the team checked levels of HMGA2 and compared them to how each patient responded to treatment. They found that patients with high levels of HMGA2 were more than twice as likely to have succumbed to their disease. They also were more likely to have cancer spread to distant sites.
The results jibe with previous research that linked overexpression of HMGA2 to poor prognosis of several other cancers, Ann said.
In contrast, however, the researchers found that higher HMGA2 levels made tumor cells more sensitive to radiation therapy.
“HMGA2 prevents cells from repairing their DNA when it is damaged by radiation,” Ann said. “This finding correlates with our previous findings that patients with HMGA2-positive colorectal tumors responded positively when we added radiation therapy to their treatment regimens.”
The researchers suggest that HMGA2 could be used to gauge which treatments to use — and how aggressively to use them — for individual patients, but they caution that further studies are needed.
Excepting skin cancer, colorectal cancer is the third most common form of cancer in men and women, according to the American Cancer Society. More than 140,000 new cases were diagnosed in the U.S. last year, and more than 51,000 people died of the disease.
Xiaochen Wang, M.D., Ph.D., of Zhejiang University, and City of Hope’s Xiyong Liu, Ph.D., were first authors on the study. Other City of Hope researchers include Angela Ying-Jian Li, Ph.D., Lily Lai, M.D., Her Helen Lin, Ph.D., Shuya Hu, Sofia Loera, Lijun Xue, Ph.D., Bingsen Zhou, Ph.D., and Peiguo Chu, M.D., Ph.D.
The study was supported by the National Institutes of Health.