TUESDAY, July 31 (HealthDay News) -- A new study finds a strong correlation between certain genes passed down through families and the odds of multiple colon polyps discovered by colonoscopy.
The findings could point the way to deciding who will benefit from gene testing when assessing risks for colon cancer, the study's authors said.
Two "germline mutations" -- DNA changes passed down from parent to offspring -- are often implicated when multiple colorectal adenomas (polyps) are found in people with a condition called familial adenomatous polyposis, noted a team led by Dr. Shilpa Grover, of Brigham and Women's Hospital in Boston.
However, there is no consensus on when genetic testing for the two genes, known as APC and MUTYH, should be done.
In the new study, published in the Aug. 1 issue of the Journal of the American Medical Association, Grover and colleagues looked at data on almost 8,700 people who had undergone full genetic mapping between 2004 and 2011.
The researchers found that 80 percent of people with 1,000 or more polyps also carried the APC mutation, whereas just 2 percent carried the MUTYH mutation. Rates of the APC mutation were also much more prevalent than MUTYH among people with between 100 and 999 polyps, the study found.
However, the rate of either of the mutations was similarly low (estimated at 10 percent of patients or less) for people with fewer adenomas (between 10 and 99 polyps).
The bottom line: The number of colorectal polyps a patient had "was strongly associated" with the presence or absence of these genetic mutations, the researchers said.
Based on the finding, the investigators reasoned that testing for APC or MUTYH might be considered for anyone with 10 or more polyps detected on colonoscopy. "However, our results are derived from a selected cohort [group] of high-risk individuals and need to
All rights reserved