A simple mucus test for cancer screening.

Comparative and correlative studies of the pathology and pathogenesis of colon cancer in animal models and human disease have resulted in conceptualization of 'field effect" theory and identification of markers that are expressed early during carcinogenesis. This assimilated body of knowledge has resulted in development of a simple rectal mucus test for colon cancer screening. The marker galactose-N acetylgalactosamine (Gal-GalNAC) is expressed in the rectal mucus of patients with colonic cancer or precancerous lesions and is detected by enzymatic oxidation (10 minutes) followed by color reaction (1 minute). The high sensitivity, specificity, positive predictive value and negative predictive value, as well as the cost-effectiveness of this test makes it a great tool in our strategies for early detection, hence control of colon cancer. Because of its high accuracy (as opposed to the fecal occult blood tests), it would reduce the number of unnecessary colonoscopies, thereby decreasing the total national health-care cost to the society. Similar expression of this marker in cancers of breast, lungs, prostate, pancreas, makes it a potentially useful general cancer screening test.