Reuters Health, Oct 20, 2006 Blocking the enzyme aldose reductase prevents proliferation of human colon cancer cells and arrests tumor progression in mice, researchers report in the journal Cancer Research. Moreover, they point out, drugs that block this enzyme already exist. "Since an inhibitor is being used in Japan under the trade name Epalrestat for the prevention of secondary diabetic complications, and at least three new inhibitors are (in) clinical trials in the U.S., it will be easier to start the clinical trials for colon cancer using these inhibitors," Dr.Satish K. Srivastava told Reuters Health. Dr. Srivastava is a researcher at the University of Texas Medical Branch in Galveston.