CDX2 and gastric cancer: To further elucidate the molecular mechanisms behind the inactivation of the CDX2 gene, we detected the promoter methylation status by methylation-specific PCR (MSP) and the expression of CDX2 mRNA and protein by real-time fluorescence quantitative polymerase chain reaction (RFQ-PCR) and western blotting in the GC cell lines AGS, MKN-45 and SGC-7901.