DETECTION OF CARCINOEMBRYONIC ANTIGEN-EXPRESSING FREE TUMOR-CELLS IN PERITONEAL WASHES FROM PATIENTS WITH GASTRIC-CARCINOMA BY POLYMERASE CHAIN-REACTION

Cytological examination of peritoneal washes is a useful predictor of peritoneal recurrence in gastric carcinoma patients. In the present st udy, even more sensitive detection of free cancer cells could be achie ved through amplification of carcinoembryonic antigen (CEA) mRNA by me ans of the reverse transcriptase-polymerase chain reaction (RT-PCR). C EA was first confirmed to be present in all the gastric cancer cell li nes examined, irrespective of the differentiation degree, and absent i n blood and mesothelium, indicating the specificity of this approach f or detection of carcinoma cells in peritoneal lavage fluid. In sensiti vity tests, CEA RT-PCR proved to be capable of detecting 10 carcinoma cells per sample. Peritoneal washes of 15 of 48 gastric carcinoma pati ents, including all 10 patients with positive cytology results, proved positive for CEA mRNA. None of the 5 patients with benign disease was positive. Moreover, a close association with the depth of cancer inva sion was established. The results indicate that the assay is more sens itive for detection of free carcinoma cells in the peritoneal cavity t han conventional cytology. This is the first study to suggest the feas ibility of the RT-PCR method for prediction of peritoneal recurrence i n gastric cancer patients.