PEBP1 and esophageal squamous cell carcinoma: Several studies of tumors, including gastric adenocarcinomas [18,19], esophageal squamous cell carcinomas [20,21], colorectal cancers [22,23], and breast cancers [24], reported that methylation status of the RKIP promoter determined by MSP (methylation specific PCR) strongly correlated with low RKIP expression levels in various advanced stages of the tumors.