ANAHEIM, California (Reuters Health) - Expression of the adenomatous polyposis coli (APC) tumor suppressor gene in normal colonic mucosa differs between individuals with and without sporadic colorectal adenomatous polyps, according to a new report. Reduced APC expression may serve as a potential biomarker for risk of adenomas and sporadic colon cancer, the study investigators suggest.
Dr. Aasma Shaukat from Emory University in Atlanta presented the findings Sunday at the 96th annual meeting of the American Association for Cancer Research.
“We know that APC is the gatekeeper pathway that pretty much controls the progression when normal epithelium starts becoming dysplastic, forms an adenoma and then forms cancer,” Dr. Shaukat explained in an interview with Reuters Health.
“APC is mutated in 80% of sporadic colon carcinomas so the idea of our study was to see how early these changes start -- meaning for somebody who already has a polyp on a colonoscopy -- has their APC level started going down compared with somebody who does not have a polyp?” she said.
To investigate, she and colleagues conducted a colonoscopy-based case-control study, involving 49 adults with adenomas and 152 controls. Dr. Shaukat’s group measured APC using automated immunohistochemistry and quantitative image analysis software.
Initial findings in the first 20 cases and 22 controls show that mean levels of log-transformed APC expression were decreased in cases compared with controls. “The proportional difference between cases and controls was -44%, which is significant,” Dr. Shaukat said.
“These results suggest that APC may be mutated very early on in people who are forming polyps versus people who are not, and perhaps this is a biomarker that people could be screened for during colonoscopy,” she said.
The results of multivariate logistic regression analysis exploring associations of APC expression with environmental, clinical, and nutritional risk factors suggest that APC expression may be modified by diet and lifestyle factors.
“There were some trends but no significant associations -- maybe because the sample size is small,” Dr. Shaukat said. This is something to study further, she added.
MeSH Headings:Biological Factors: Congresses: Health Care Economics and Organizations: Immunologic and Biological Factors: Organizations: Tumor Markers, Biological: Biological Markers: Genes, APC: Chemical Actions and Uses: Chemical Actions: Chemicals and Drugs: Health CareCopyright © 2002 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.
