Related Experiment Videos
MSH2 deficiency contributes to accelerated APC-mediated intestinal tumorigenesis
A H Reitmair1, J C Cai, M Bjerknes
1Amgen Institute, Ontario Cancer Institute, Department of Medical Biophysics, University of Toronto, Canada.
Cancer Research
|July 1, 1996
Summary
DNA mismatch repair (MMR) gene defects accelerate intestinal tumor development. MSH2 deficiency in mice led to more numerous and faster-growing adenomas, highlighting MMR genes
Area of Science:
- Genetics
- Oncology
- Molecular Biology
Background:
- Hereditary nonpolyposis colorectal cancer (HNPCC) is linked to germ line DNA mismatch repair (MMR) gene defects.
- Defects in MMR genes are thought to cause rapid replication errors in critical genes like APC (adenomatous polyposis coli).
- Accelerated intestinal tumorigenesis is a hallmark of HNPCC.
Purpose of the Study:
- To investigate the role of MMR genes in accelerated intestinal tumorigenesis.
- To determine the mechanism of APC allele inactivation in the context of MMR deficiency.
Main Methods:
- Crossed the Min mouse (heterozygous for Apc mutation) with an Msh2-deficient mouse.
- Analyzed colonic aberrant crypt foci, adenoma development, survival rates, and APC allele inactivation mechanisms.
- Utilized immunostaining to assess APC protein expression and loss of heterozygosity analysis.
Main Results:
- MSH2 deficiency significantly increased the number of colonic aberrant crypt foci and adenomas.
- Mice with MSH2 deficiency exhibited reduced survival due to more numerous and rapidly developing adenomas.
- APC allele inactivation mechanisms differed based on MSH2 status, with somatic mutations playing a role in MSH2-deficient mice.
Conclusions:
- MMR genes, specifically MSH2, play a critical role in preventing accelerated intestinal tumorigenesis.
- Somatic APC mutations contribute to tumor development in the absence of functional MMR.
- Findings support more aggressive surveillance for colorectal cancer in HNPCC patients.