Purpose: The objective of the present study was to evaluate the gene expression of the DNA mismatch repair gene MSH2 as a predictive marker in advanced colorectal cancer (CRC) treated with first-line capecitabine.
Patients and methods: Microdissection of paraffin-embedded tumor tissue, RNA extraction, and quantitative polymerase chain reaction were performed on tumors obtained from 37 patients with advanced CRC.
Results: The median relative gene expression of MSH2 was 0.65 (quartiles 0.5-0.8) in nonresponders and 1.25 (quartiles 0.92-1.38) for responders (P = 0.038). High expression of MSH2 was associated with a hazard ratio of 0.5 (95% confidence interval, 0.23-1.11; P = 0.083) in survival analysis.
Conclusion: The higher gene expression of MSH2 in responders and the trend for predicting overall survival indicates a predictive value of this marker in the treatment of advanced CRC with capecitabine.