These findings, combined with our present data, suggest that downregulation of SOX2 through aberrant DNA methylation and resultant alteration of cyclin D1 and p27Kip1 protein levels may be associated with poor prognoses in gastric cancers, and that SOX2 methylation can be a clinically useful prognostic marker for advanced gastric cancer patients. Here, CDKN1B is linked to gastric cancer.