Demethylation of the CD133 Gene Is Frequently Detected in Early Gastric Carcinoma

Background: Recently, it has been reported that colorectal carcinoma is created and propagated by a small number of undifferentiated tumorigenic CD133(+) cells. Furthermore, it has been reported that CD 133 expression is directly regulated by epigenetic modifications. Therefore, it is possible that CD133 expression by gene demethylation is related to colorectal and gastric carcinogenesis. Materials and Methods: The methylation status of the CD133 gene was examined in primary carcinomas and the corresponding normal tissues derived from 36 patients with gastric cancer using quantitative methylation-specific polymerase chain reaction (qMSP) and the correlation between the methylation status and the clinicopathological findings was evaluated. Results: Demethylation of the CD133 gene was detected in 14 out of the 36 (39%) primary gastric carcinomas, suggesting that the demethylation of CD133 is frequently observed in gastric carcinomas. The clinicopathological data were correlated with the demethylation results. A significant decrease of CD133 methylation was observed in the extent of tumor (p=0.0421). Moreover, a trend was shown toward smaller maximal tumor size in tumors with demethylated CD133 (p=0.0556). Conclusion: CD133 appears to be frequently demethylated in early gastric carcinomas.