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Community Cancer Center Study Investigates the Genetics of Colorectal Cancer

Date: 06.04.2011
Contact: Jennifer Farquhar Phone: (330) 375-4930

Contact: Jennifer Farquhar, Phone: (330) 375-4930 Email:

CHICAGO, June 4, 2011 – Lynch Syndrome (a type of hereditary colon cancer) comprises 3 to 5 percent of colorectal cancers. Younger age at diagnosis, a strong family history and certain pathologic changes help identify these patients. The results of subsequent genetic testing have implications for the patients and for their family members.

There are certain pathologic characteristics, primarily a deficient mismatch repair protein status, that are almost universally present (>90 percent) in patients with Lynch Syndrome. However, the majority of patients with this pathologic characteristic do not test positive for Lynch Syndrome. Beginning in March 2010, researchers at Summa Health System in Akron, Ohio, tested 128 colorectal cancer patients to see the overall incidence of mismatch repair protein deficient colorectal cancers and the contribution of BRAF mutation (which is thought to be an acquired abnormality associated with mismatch protein defects) and the incidence of Lynch Syndrome especially in this subset of patients.

  1. “With this study, we hope to add to the growing body of knowledge about when genetic testing is most appropriate,” said Hematologist/Oncologist Sameer Mahesh, MD, who served as an investigator on the study, which is being presented on a poster at the American Society of Clinical Oncology Annual Meeting on June 4 in Chicago. “We found that in 81 percent of the cases that had an absence of MLH1 – the most common mismatch repair protein defect – the patient had an acquired defect and not a hereditary cancer. This saves the patient and family significant anxiety while awaiting the test results in addition to cost savings since genetic testing is expensive.”

Pathologists test for four proteins (mismatch repair proteins) when looking for genetic colon cancer including: MLH1, PMS2, MSH2 and MSH6. The absence of any of these may indicate that the patient has Lynch Syndrome; however, if MLH1 is deficient, BRAF was tested for the V600E mutation. If mutated, the defect is acquired, and there is no need for genetic testing for Lynch Syndrome. In Summa’s study, 16 of the 128 biopsies did not express MLH1, 13 of those had mutated BRAF, and 12 of these were from females with right-sided colon cancer (in the ascending colon and cecum). The study did not find an increased detection rate for Lynch Syndrome when mismatch repair protein testing was routinely done in all colorectal cancer patients.

“It was interesting that tumors lacking MLH1 were predominantly BRAF mutated and from older women that had right-sided colon cancer,” Dr. Mahesh said. “This adds to the growing body of knowledge on the different driving forces for colorectal cancer”

About Summa Health System
Summa Health System is one of the largest integrated healthcare delivery systems in Ohio. Encompassing a network of hospitals, community health centers, a health plan, a physician-hospital organization, a multi-specialty physician organization, research and multiple foundations, Summa is nationally renowned for excellence in patient care and for exceptional approaches to healthcare delivery. Summa's clinical services are consistently recognized by the American Nurses Credentialing Center (Magnet® status), U.S. News and World Report, Thomson Reuters and The Leapfrog Group. Summa also is a founding partner of the Austen BioInnovation Institute in Akron. For more information, visit or find us on Facebook at and Twitter at