Polymerase chain reaction for detection of carcinoembryonic antigen-expressing tumor cells on milky spots of the greater omentum in gastric cancer patients: A pilot study

Our recent studies indicate that omental milky spots are frequently involve d in the early stage of peritoneal cancer dissemination. We have used carci noembryonic antigen (CEA)-specific RT-PCR for omental milky spots to predic t peritoneal recurrence in gastric cancer patients. CEA mRNA was found to b e positive in both 10 peritoneal washes and 16 greater omenta of 30 gastric cancer patients, including all 6 patients who showed positive results for both cytology and RT-PCR of peritoneal wash and omentum. Three of the 6 cas es with positive RT-PCR in the greater omentum but not in the peritoneal wa sh showed recurrence of peritoneal carcinomatosa within 2 years after opera tion. Micrometastasis on omental milky spots was histologically confirmed i n 6 of 30 gastric cancer cases. Non-specific band was detected only in the omentum of 1 case of 15 benign disease (7%), but not in peritoneal washes ( 0%), probably due to weak expression of CEA in mesothelial cells. Our resul ts show that CEA- specific RT-PCR targeting micro-metastases on omental mil ky spots is more sensitive than targeting the peritoneal wash or convention al cytology, and suggest that this method is useful for the prediction of p eritoneal recurrence in gastric cancer patients. (C) 2001 Wiley-Liss, Inc.