CD133 mRNA expression and microsatellite instability in colorectal carcinoma.

OBJECTIVE

The present study was performed to examine the CD133 expression in colorectal cancer and to analyze its relationship with microsatellite instability (MSI) and the clinicopathological factors, including patient survival.

METHODS

The CD133 mRNA levels in 61 primary colorectal adenocarcinomas were analyzed by reverse transcriptase-polymerase chain reaction, with normalization relative to GAPDH. Five microsatellite markers were analyzed to evaluate MSI.

RESULTS

A CD133 mRNA expression was significantly associated with the depth of invasion (P = 0.017), lymph node involvement (P = 0.012), and lymphovascular invasion (P = 0.019). A CD133 expression was significantly correlated with the MSI status (P = 0.035). With a median follow-up period of 45 months, the 5-year disease-free survival rate of patients with a low CD133 mRNA expression was significantly higher than that of those patients with high levels of CD133 mRNA expression (82.9% and 59.0%, respectively; P = 0.027). However, on the multivariate analysis, a CD133 mRNA expression was not an independent predictor of disease-free survival.

CONCLUSIONS

Elevated CD133 mRNA levels may represent more aggressive tumor biology and poorer survival in patients with colorectal cancer, correlating with a high level of MSI status. Larger prospective studies are required to confirm these findings.