Predicting Response to Chemotherapy in Colon Cancer

Biomarkers can predict which patients can best respond to chemotherapy for stage II colon cancer according to findings published in the New England Journal of Medicine.

Researchers from Columbia University Medical Center and the University of California, San Diego searched for biomarkers of colon epithelial differentiations across 466 patients and more than 2,000 tumor samples to determine which could predict viable candidates for successful chemotherapy treatment for stage II colon cancer.

The study authors noted that prior studies demonstrated the ability of biomarkers to show what stage II colon patients are at a high risk for relapse after surgery. However, these biomarkers are not able to predict the status of these patients after chemotherapy treatment.

The investigators discovered 16 biomarkers that were eligible for further study.

One gene, called CDX2, was found to hold up during standardized diagnostic testing for detecting gene expression. The gene had already been found to regulate cell differentiation in the colon lining. But now, the researchers learned that patients without CDX2 expression had a poorer prognosis compared to patients’ tumors, which expressed CDX2.

“We wanted to understand if the small group lacking CDX2 expression — approximately 4% of the global colon cancer population—fared poorly because of an intrinsic resistance to chemotherapy,” first author Piero Dalerba, MD explained in a press release. “To our surprise, we found that, on the contrary, tumors lacking CDX2 expression, despite being very aggressive from a biological point of view, also appeared to benefit from early treatment with adjuvant chemotherapy.”

Dalerba added that the CDX2 test is inexpensive and simple, plus it is already widely available. Even though additional studies are still needed to confirm the findings and to test CDX2’s viability as a decision making tool for cancer patients, it is still an important stepping stone.

“While promising, this study was retrospective, meaning we looked back at existing patient data,” first author Debashis Sahoo, PhD explained in another statement. “Before they can be applied to clinical practice, these results need to be confirmed by prospective, randomized clinical trials.”