MONDAY, May 5 (HealthDay News) -- The overproduction of a protein may be what starts harmless colon polyps on their journey to becoming malignant tumors, Finnish researchers report.

The University of Helsinki research, published online in Cancer Cell, reveals that PROX1, a protein that controls formation of normal organs in embryos, is produced in excess during the early stages of cancer development. PROX1 even encourages tumor cell growth without additional signals from surrounding normal tissues.

The removal of PROX1 from cancer cells appears to reverse their malignant behavior, suggesting that future research may focus on the protein's use in colon cancer therapies.

Men and women face a lifetime risk of nearly 6 percent for the development of invasive colorectal cancer, making it one of the most common malignancies in the Western world. Past epidemiologic studies have cited obesity and several dietary factors -- including fat, red meat and a lack of vegetables and fiber -- as increasing the risk of the disease.