Researchers advance the possibility of genetic testing for colorectal cancer

Of the 106,100 new cases of colon cancer worldwide, the American Cancer Society estimates that a disproportionately large number of those - 40,870 - are in the United States. While better screening methods are believed to have contributed to a declining death rate from the disease over the past 20 years, colonoscopies, which look for suspicious polyps, often miss tumors. The polyps may be too small, and says Dr. Jerald Wishner, director of the colorectal cancer program at Northern Westchester Hospital in Mount Kisco, N.Y., "The success of colonscopies to detect small polyps depends upon the skill of the person performing the procedure." There are other key challenges: the high cost and involved preparation process preclude some people from getting colonoscopies, and there are too few gastroenterologists to meet the need.

Against this backdrop, a team of international scientists from the Netherlands, Belgium and the United States believe that genetic screening of colorectal cancer holds real promise. And in fact, they say they are moving closer to the development of a genetic test that may indicate who should undergo the more advanced colonoscopy.

According to a study published online in the Journal of the National Cancer Institute, the researchers have found a genetic red flag that indicates colon cancer 53 percent of the time in stool samples. They looked for genetic signs that appeared in cancerous colorectal cells and tissue, but not in those from healthy individuals. "The gene-based tests are based on the assumption that a tumor will shed cells into the stool," says Dr. Gad Rennert, director of the CHS National Israeli Cancer Control Center. Dr. Rennert wrote a commentary on the study, stating that "these cells, when isolated from the stool which is collected at home, have genetic characteristics which can be identified and suggest that there is risk." Unfortunately, 53 percent indication is not enough to turn the test into a useful screening tool. But predicts Dr. Wishner, "While the research is in its preliminary stages, molecular genetics will likely be the future of colon cancer screening."

News Release: Study finds possible genetic indicator of colorectal cancer  www.forbes.com    June 18, 2009