TRYPSINOGEN EXPRESSION AND EARLY DETECTION FOR PERITONEAL DISSEMINATION IN GASTRIC-CANCER

Background and Objectives: The most reliable method for the diagnosis of peritoneal dissemination of gastric cancer at the present time is c ytological examination of ascitic fluid, which is unavailable to patie nts without ascites or may be inadequate for those with ascites contai ning few cancer cells. It has been reported recently that human gastri c cancer immunoreacted with a monoclonal antibody against pancreatic t rypsinogen. We therefore examined the expression of trypsinogen as a n ew marker for the early diagnosis of peritoneal dissemination of gastr ic cancer. Methods: Pancreatic trypsinogen protein was immunohistochem ically stained with a three-step indirect immunoperoxidase method and cationic trypsinogen (trypsinogen-1) mRNA expression was examined by r everse transcriptase-polymerase chain reaction (RT-PCR) analysis in ga stric cancer. Twenty-nine of 30 primary tumors (97%) and all 12 tumors (100%) of the peritoneal seedings immunohistochemically reacted with trypsinogen. Preliminary study for early diagnosis of peritoneal disse mination was carried out for eight more recent patients who showed pos itive immunoreactivity to trypsinogen protein and expressed trypsinoge n-1 mRNA in the primary tumor. The expression of trypsinogen-1 mRNA wa s detected by using peritoneal lavage fluid preoperatively collected i n these patients. Results: All three patients in whom peritoneal disse mination was diagnosed at the time of their operation(s) expressed try psinogen-1 mRNA. One patient, who did not show peritoneal disseminatio n at the operation but was positive for trypsinogen-1 mRNA detection, later died of the recurrence of peritoneal dissemination. Conclusions: These results indicated that trypsinogen protein and trypsinogen-1 mR NA frequently expressed in peritoneal dissemination as well as primary tumors in gastric cancer and detection of trypsinogen-1 mRNA expressi on was a useful method for early diagnosis in peritoneal. disseminatio n of gastric cancer. (C) 1998 Wiley-Liss, Inc.