EXPRESSION OF MESSENGER-RNA FOR HEREGULIN AND ITS RECEPTOR, ERBB-3 AND ERBB-4, IN HUMAN UPPER GASTROINTESTINAL MUCOSA

Expression of mRNA for heregulin (HRG), a member of the epidermal grow th factor (EGF) family and its receptors, ErbB-3 and ErbB-4, were. eva luated in human upper gastrointestinal; (GI) mucosa. Multi-target reve rse-transcriptase polymerase-chain reaction (RT-PCR) analysis using ca pillary electrophoresis and laser-induced fluorescence allowed us to q uantify the minute amounts of mRNA from one biopsy specimen with high sensitivity. -HRG, ErbB-3 and ErbB-4 mRNA were detected in esophagus, stomach and duodenum and the highest expression was found in duodenum. In gastric cancer, mRNA for ErbB-4 was significantly overexpressed. I mmunoreactivity of ErbB-4 in carcinoma cell membrane was also confirme d. These findings suggest that HRG and its receptors, ErbB-3 and ErbB- 4 may be physiologically significant in the human upper GI mucosa, esp ecially in duodenum, and that ErbB-4 may contribute to the growth of g astric cancer.