MOLECULAR-BIOLOGY AND IMMUNOHISTOCHEMISTR Y OF GASTRIC-CANCER - ANALYSIS OF HER2 NEU ONCOGENE/

In 58 gastric carcinomas the expression of the Her2/neu gene product p 185 was immunohistochemically analyzed. Fresh tumor tissue for molecul ar studies was available in 25 cases. The results were correlated with various pathohistological and prognostic factors. A 16-32fold Her2/ne u amplification was found in 20% of the tumors (n = 5). The oncogene p roduct p185 was detected at the basement membrane in 38 % of the tumor s (n = 22). Amplification and p185 overexpression occurred in intestin al, but not diffuse type carcinomas (p < 0.001). p185 expression was i ndependent from tumor site and tumor stage, but correlated with pT-sta ge (p < 0.001). Overall prognosis was influenced by tumor stage and R- classification, but not by p185 expression. Multivariate analysis, how ever, defined patients with stage IIIA/B and IV and R0-resection who h ad a poorer survival in case of p185 expression (p < 0.05). Her2/neu a mplification and p185 overexpression appear to be characteristic molec ular events in intestinal type gastric carcinogenesis and may help in identifying a subgroup of patients at increased risk for shorter survi val.