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Hyperplastic polyps in hereditary nonpolyposis colorectal cancer
Fleur E M Rijcken1, Tineke van der Sluis, Harry Hollema
1Department of Gastroenterology, University Hospital Groningen, Gronigen, The Netherlands.
The American Journal of Gastroenterology
|October 24, 2003
Summary
Hyperplastic polyps (HPs) in individuals with hereditary nonpolyposis colorectal cancer (HNPCC) rarely show DNA mismatch repair (MMR) gene dysfunction. This suggests HPs are unlikely precursors for MSI+ cancers in HNPCC patients.
Area of Science:
- Genetics
- Oncology
- Gastroenterology
Background:
- Hereditary nonpolyposis colorectal cancer (HNPCC) is linked to DNA mismatch repair (MMR) gene mutations.
- MMR gene dysfunction causes microsatellite instability (MSI), found in sporadic colorectal cancers.
- Hyperplastic polyps (HPs) are investigated as potential precursors for MSI+ sporadic colorectal cancers.
Purpose of the Study:
- To investigate if hyperplastic polyps (HPs) are premalignant lesions in HNPCC patients.
- To determine the prevalence of MMR gene dysfunction in HPs from HNPCC individuals.
Main Methods:
- Retrieved HPs from a screening program database for suspected MMR gene mutation carriers.
- Collected clinical data including patient age and HP location.
- Assessed MLH1, MSH2, and MLH6 protein expression using immunohistochemistry.
Main Results:
- Ninety HPs were analyzed from 40 patients (mean age 45.7 years).
- HPs were located in the proximal colon (21%), distal colon (26%), and rectum (53%).
- No HPs exhibited loss of MMR protein expression.
Conclusions:
- MMR gene dysfunction is rare in HPs from HNPCC patients.
- HPs are unlikely to be precursors for MSI+ cancers in the context of HNPCC.