Yonemura et al (2001) increased the sensitivity of detection to 62% by using a combination of CY and RT–PCR of MMP-7 mRNA. Schuhmacher et al (1999) used RT–PCR to show the relationship between the expression of E-cadherin mutation and metastasis to the peritoneum. But any assay using peritoneal wash is inferior in sensitivity and specificity when compared to the real-time RT–PCR for CEA mRNA described by Nakanishi et al. CEA is recently a standard molecular marker for the detection of gastric cancer micrometastasis. The gene discussed is CDH1; the disease is gastric cancer.