Researchers at Jefferson Medical College are finding that certain characteristics of hereditary colorectal cancer tumors may help forecast a patient's prognosis, and in turn help doctors better understand tumor biology.
Bruce M. Boman, M.D., Ph.D., Robert L. Capizzi Professor of Medicine at Thomas Jefferson University in Philadelphia, and his colleagues there and at Jefferson's Kimmel Cancer Center studied several biomarkers, including microsatellite instability (MSI). Biomarkers are proteins in tumor cells which may predict response to treatment, as well as allow better tumor classification and insight to tumor biology.
The researchers classified hereditary colorectal cancer tumor samples on the basis of MSI, according to whether it was absent, low or high. A high degree of MSI corresponds to a lack of genes responsible for DNA mismatch repair, which is vital to DNA replication. Faulty repair plays an important role in colon cancer development.
About 15 to 20 percent of colon cancer tumors, including hereditary non-polyposis colorectal cancer (HNPCC), the most common type of inherited colon cancer, have MSI, due to either an inherited or acquired mutation in a mismatch repair gene.
The scientists showed that "MSI is valuable as a pretest for DNA mismatch repair inactivation and possibly hereditary colon cancer," explains Dr. Boman, who is also director of the Division of Medical Oncology and Medical Genetics in the Department of Medicine at Jefferson Medical College. They also found "the status of microsatellite instability provides insight into the cell cycle biology of colorectal cancer."
He presents his team's findings May 15 at the annual meeting of the American Society of Clinical Oncology in Atlanta.
When mismatch repair genes go awry, the result may be colon cancer. Such
genes are part of the intricate molecular machinery that fixes the cell when DNA
damage occurs in repetitive DNA sequenc
Contact: Steve Benowitz
Thomas Jefferson University