CALGARY — A study conducted at the University of Calgary found that removing a single gene made colon cancer cells susceptible to immunotherapy. The research, which was published in the journal Cell Reports Medicine, resulted in complete tumor eradication in mouse models when the gene removal was combined with immunotherapy.

The study was led by Dr. Arshad Ayyaz, an assistant professor in the Department of Biological Sciences and a member of the Arnie Charbonneau Cancer Institute. Immunotherapy functions by training the immune system to recognize and attack tumors. Approximately 15 percent of colon cancers respond to immunotherapy treatment; immunotherapy can also reduce or eliminate the need for radiation and chemotherapy.

Researchers performed a genetic analysis comparing colon cancers that responded to immunotherapy against those that did not. This analysis showed that treatment-resistant colon tumors secrete a protein that inhibits the immune system's detection. "Only about 15 per cent of colon cancers respond to immunotherapy. We performed a genetic analysis of them against those that don't," Ayyaz observed. "The treatment-resistant tumors secrete a protein that confuses your immune system into thinking everything's fine," Ayyaz said.

The researchers created gene-edited cancer cells with the protein-coding gene removed. Tumors also shrank in the mouse models after the gene was removed even without immunotherapy treatment. Ayyaz said, "Even without the immunotherapy treatments, the tumors shrank, meaning they can't hide from the body's natural immune response anymore."

Ayyaz has researched the gut for 20 years. This research is currently in preliminary stages and is not yet ready for clinical application. The findings may eventually apply to other solid tumors, such as pancreatic or lung cancer.

No independent assessment was available for this report.