Stool test detects signs of colon cancer

A test that detects DNA cell material in a stool sample can reliably detect colorectal cancer in its earliest stages, when the disease is best treated. The colon and the rectum are parts of the large intestine. A malignant growth of cells of the large intestine is called colorectal cancer. Currently, patients are screened for cancer in a number of ways, including performing relatively uncomfortable and invasive tests such as colonoscopy. In an earlier discovery, it was noted that mutations or changes in a gene called APC are responsible for the initiation of colorectal cancers. Since this discovery, the researchers have been trying to find a way to detect APC mutations in cells shed into stool. The concept is simple, but finding the mutated genes had been a difficult task. In a research carried out at the Kimmel Cancer Centre at Johns Hopkins in Baltimore, Maryland the scientists developed a new technique called digital protein truncation that divides DNA from stool into smaller portions so it is easier to find the mutations. The investigators tested the screen on stool samples collected from 74 patients. The screening detected APC mutations in 17 of 28 patients with early-stage cancer and in 9 of 18 who had large precancerous growths. The screening test is not perfect, but its accuracy is close to the goal of detecting about two thirds of all cancer cases. Also, it did not produce any false-positive results. None of the 28 patients who did not have cancer tested positive for APC mutations. This test still needs to be refined and tested in a larger study, before it can become widely acceptable.

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