Test for Protein in Stool Samples Detects Colon Cancer

A new test based on detection of a protein in stool samples appears to be a noninvasive and accurate method of detecting colon cancer, British researchers reported in The Lancet.

Dr. Nicholas Coleman of the MRC Cancer Cell Unit in Cambridge said the minichromosome maintenance protein 2 (MCM2) was found in stool samples of 37 of 40 patients with symptomatic colorectal cancer.

None of the cells from 25 healthy subjects in a control group expressed MCM2, he reported.

The MCM2 protein is present in normal large bowel mucosa, but it only is found in cells on the surface of the colon when polyps or cancer are present. Researchers theorized that in patients with cancer, cells with MCM2 protein might be sloughed off and be detectible in the stool.

The researchers used three different methods of retrieving cells with the MCM2 protein from the stool: a direct smear method, a centrifugation technique, and a magnetic microbead technique. They reported that the direct smear and centrifugation techniques retrieved MCM2-positive cells in significantly more cases than the microbead technique.

"Despite the requirement for rapid stool processing, our approach might ultimately prove suitable for population screening, either alone or in combination with other tests," the researchers concluded.

Other sources: The Lancet