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Defective Mismatch-Repair Colorectal Cancer
Clinicopathologic Characteristics and Usefulness of Immunohistochemical Analysis for Diagnosis

Rodrigo Jover MD, Artemio Payá MD, Cristina Alenda MD, María J. Poveda MD, Gloria Peiró MD, F. Ignacio Aranda MD, Miguel Pérez-Mateo MD
DOI: http://dx.doi.org/10.1309/V9PGK2Y260VFVULR 389-394 First published online: 1 September 2004


The purpose of our study was to determine the usefulness of immunohistochemical analysis for the diagnosis of mismatch-repair (MMR) gene defective colorectal tumors and to describe their prevalence and clinicopathologic characteristics. We studied 172 cases. DNA was extracted from formalin-fixed, paraffin-embedded surgical samples, and microsatellite analysis was performed by polymerase chain reaction with BAT-26. The results were correlated with immunohisto-chemical analysis for hMLH1 and hMSH2. Microsatellite instability (MSI) was detected in 13 (7.6%) tumors, and all showed loss of protein expression of hMLH1 (11/13) or hMSH2 (2/13) (P < .000). Patients with MMR-defective tumors more frequently had poorly differentiated tumors (5/13 [38%] vs 18/159 [11.3%]; P = .02) located in the ascending colon (8/13 [62%] vs 30/159 [18.9%]; P < .0001) and a personal history of other neoplasms (4/13 [31%] vs 18/159 [11.3%]; P = .05). There were no differences in age, family history of cancer, or TNM stage. Immunohistochemical analysis seems to be a reliable method to detect most colorectal cancers with defective MMR genes.

Key Words:
  • Colorectal cancer
  • CRC
  • DNA repair
  • Microsatellite instability
  • MSI
  • Immunohistochemistry
  • Hereditary nonpolyposis colorectal cancer