Variability in microsatellite instability in sporadic colon cancer
- Northwestern Univ., Evanston, IL (United States); and others
The phenomenon of microsatellite instability recently has been described in colon cancer. However, little attention has been given as to whether different microsatellites have different degrees of instability in cancer patients. We selected a total of 14 microsatellite loci (5 di-, 3 tri-, 6 tetranucleotide) supposed to have different mutation rates in vivo, and spread over 8 different chromosomes. The above microsatellites were typed by PCR analysis of DNA from a total of over 200 paraffin-embedded colon tumors and corresponding normal tissue. None of these patients have an obvious family history of cancer and thus we assumed all tumors were sporadic. Comparison of normal and colon cancer tissues revealed somatic mutations for each of the selected microsatellites. The proportion of patients with instability for any given locus varies from 4.5% to 19.3%, with tetranucleotide repeats having the highest average frequency. In addition, a greater fraction of tumors showed instability in at least 1 locus than previously has been reported, possibly signifying a baseline microsatellite instability in all colon cancers. For cases demonstrating instability at 1 or more loci, we analyzed additional microsatellite loci. We then grouped patients based on the number of loci that showed instability. In order to investigate patterns of instability, we also scored the size of somatic mutations occurring in cancer tissue.
- OSTI ID:
- 133587
- Report Number(s):
- CONF-941009--
- Journal Information:
- American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
- Country of Publication:
- United States
- Language:
- English
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