Objective     To compare detection of STAT3 and CEA by nest RT-PCR and peritoneal lavage cytology examination (PLC) in predicting peritoneal micrometastasis in gastric carcinoma patients.      Methods     Peritoneal washings of 66 patients with gastric carcinoma and 12 patients with benign gastric diseases were collected to detect the mRNA level of STAT3 and CEA by nest RT-PCR. PLC were carried out by H-E staining.      Results     The positive rates of STAT3 mRNA and CEA mRNA in peritoneal washings were 43.9% and 48.5%

respectively. The positive rates of STAT3 mRNA and CEA mRNA were significantly higher than those of PLC (31.8%). The positive rates of STAT3 mRNA and CEA mRNA were concurrently increased with the depth of tumor invasion

TNM staging and pathogenesis.      Conclusion     Detecting STAT3 mRNA in peritoneal washings by nest RT-PCR can improve the sensitivity of free tumor cell detection in peritoneal washings

and may be used to predict peritoneal micrometastasis of gastric carcinoma.