# Stool Test Detects Colon Cancer



## wanderingstar (Dec 1, 1999)

http://www.medscape.com/viewarticle/434396?srcmp=gas-053102


> quote:*Immunocytochemical Stool Test Detects Colon Cancer*LONDON (Reuters Health) May 30 - *A new stool-based assay, which tests for colonocytes expressing a DNA replication protein, appears to be a sensitive and specific method of detecting colon cancer, according to a report published in the June 1st issue of The Lancet. *Minichromosome maintenance protein 2 (MCM2), the protein detected by the test, is present in normal colon mucosa, but its expression is limited to the basal region of colonic crypts. However, when an adenoma or carcinoma is present, MCM2 is expressed throughout the epithelium and therefore cells expressing the protein could be sloughed into the stool. In the current study, Dr. Nicholas Coleman and colleagues, from the MRC Cancer Cell Unit in Cambridge, UK, tested three different methods of retrieving colonocytes from stool samples. These included a direct smear method, a centrifugation technique, and a magnetic microbead technique. After cell retrieval, a monoclonal antibody was applied to test for the presence of MCM2. The researchers tested the MCM2 assay on stool samples from 40 patients with symptomatic colorectal cancer and 25 healthy control subjects. Of the cancer patients, 32 had left-sided lesions and 8 had right-sided lesions. None of the cells from the healthy subjects expressed MCM2. In contrast, MCM2-expressing cells were found in 37 of the cancer patients. The three cancer patients in whom no MCM2-expressing cells were found had right-sided colon lesions, the authors point out. As for the cell retrieval methods tested, direct smear and centrifugation techniques retrieved MCM2-positive cells in significantly more cases than the microbead technique (p < 0.0001). "The conditions of this study do not represent those of a general screening setting, and our findings might have differed in a population with a higher frequency of right-sided cancers," the investigators note. Still, despite the need to process the stool samples rapidly, the MCM2 assay could represent a useful screening test either alone or combination with other assays, they add.Lancet 2002;359:1917-1918.


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