Colon cancer may be treatable with hormone therapy

Colon cancer —a disease triggered by deactivated hormones — might eventually be treated with hormone therapy, scientists say.

A study in the Aug. 1 issue of the journal Gastroenterology finds that GCC, a protein receptor on the surface of intestinal epithelial cells for two hormones, guanylin and uroguanylin, can suppress tumour formation. These hormones regulate the growth of the intestinal cells.

Early in colon cancer development, these growth-controlling hormones aredeactivated, disrupting GCC's activity and contributing to tumour formation, Scott Waldman,chair of pharmacology and experimental therapeutics at Jefferson Medical College, said in a release.

The finding "converts colon cancer from a genetic disease, which is the way we've all thought about it, to a disease of hormone insufficiency," said Waldman. "It's a completely different way of thinking about the disease.

Using two separate mouse models that mimic the development of colon cancer in people, researchers showed that GCC signaling blocks cancerous tumours from forming in the colon. When GCC was removed from the mice and a carcinogen introduced, researchers found tumours larger and ingreater number in both the colon and intestines.

The same scenario occurred in mice that carried a mutation of the APC gene, which causes the growth of colon polyps that lead to colon cancer.

Taken together, exposure to a carcinogen or mutations in APC, along with the loss of GCC signaling is "a recipe for colon cancer," Waldman said.

Researchers would like to extend this study to show that by treating patients with hormone replacement therapy, intestinal cancer formation can either be prevented or treated.