Colon cancer: Lowering ammonia levels increases tumor treatment response

Colorectal cancer, also known as bowel or colon cancer, is the third most common type of cancer and the second most common cause of cancer death around the world. There is currently no cure for colorectal cancer. Treatment options include surgery, chemotherapy, immunotherapyTrusted Source, radiation therapy, or a colectomy.

Now, researchers from the University of Michigan Medical School have found high levels of ammoniaTrusted Source in colon tumors keep them from responding well to immunotherapy. They say using the FDA-approved drug hyperammonemia helps reduce the tumor’s ammonia levels, making it more sensitive to treatment.

The studyTrusted Source was recently published in the journal Cell Metabolism.

Ammonia and colon cancer

Ammonia is one of the body’s naturally occurring waste products.

The body makes ammonia during the digestion process, which is then moved to the liver where it is turned into ureaTrusted Source and removed from the body during urinationTrusted Source.

Why do colorectal tumors have a high level of ammonia in the first place — is that something normal?

Yes, said Dr. Anton Bilchik, a surgical oncologist and division chair of general surgery at Providence Saint John’s Health Center and chief of medicine and Director of the Gastrointestinal and Hepatobiliary Program at Saint John’s Cancer Institute in California who was not involved in the study.

“Our body has 2 trillion bacteria called the microbiome,” he explained to Medical News Today. “The thought is that there’s some disruption in the bacteria in patients with colon cancer that leads to the breakdown of certain products that increase the amount of ammonia in colon cancer cells.”

“In colon cancer, there appears to be a disproportionate amount of ammonia compared to normal cells, because of these bacteria within our body that are disrupted and not functioning normally,” Bilchik added.

“Moreover, normal intestinal cells can detoxify this via the urea cycle enzymes, but colon cancer can’t do this very well as most of the enzymes in the urea cycle are decreased in cancer,” said Dr. Yatrik Shah, a professor of physiology, molecular and integrative physiology, and internal medicine at the University of Michigan Medical School and corresponding author of the study.