As part of the normal turnover that occurs in the cells that line the bowel, many of the epithelial cells that line the intestines are shed into the waste. As discussed in the section on tumor suppressors, many colon cancers share a common genetic defect in the APC gene. The cells that are shed into the fecal matter contain DNA and tests have been developed to detect mutations in the APC gene. This technique is able to detect the DNA from colon cancer cells even at early stages of cancer. Its non-invasive nature makes it a promising new screening tool.(1)(2)
For more information about colorectal cancer visit the Winship Cancer Institute of Emory University.