Stains & molecular markers
Microsatellite instability
Copyright: 2002-2021, PathologyOutlines.com, Inc.
PubMed Search: Microsatellite instability [title]
Microsatellite instability
Author: Nat Pernick, M.D.
Topic Completed: 1 June 2005
Minor changes: 23 December 2020
Copyright: 2002-2021, PathologyOutlines.com, Inc.
PubMed Search: Microsatellite instability [title]
Table of Contents
Definition / generalCite this page: Pernick N. Microsatellite instability. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/stainsmicroinstability.html. Accessed January 20th, 2021.
Definition / general
- Changes at (CA)n and (GT)n repeats, associated with dysfunction of DNA repair mechanisms
- Involve MLH1, MSH2 proteins
- Associated with all cases of hereditary nonpolyposis colorectal cancer and 15% of sporadic colorectal cancers
- Hallmark of hereditary nonpolyposis colon cancer (HNPCC) associated tumors is defective mismatch repair, reflected in tumor tissue as microsatellite instability and loss of mismatch repair proteins MLH1, MSH2, MSH6, PMS2
- Mismatch repair defects found in 15% of sporadic colorectal cancer in > 90% of HNPCC associated cancers
- Defects present in 65% of adenomas from HNPCC patients
- Loss of staining in patient suspected of having HNPCC may be used to direct mutation analysis (Mod Pathol 2005;18:1095)
