EXPRESSION OF AMPHIREGULIN, A NOVEL GENE OF THE EPIDERMAL GROWTH-FACTOR FAMILY, IN HUMAN GASTRIC CARCINOMAS

The expression of mRNA for amphiregulin (AR), a novel gene of the epid ermal growth factor family, was examined in 8 human gastric carcinoma cell lines and 32 gastric carcinoma tissues as well as corresponding n ormal mucosa. Of the 8 gastric carcinoma cell lines, 7 expressed 1.4 k b AR mRNA at various levels. The expression of AR mRNA by TMK-1 and MK N-28 cells was increased by treatment with epidermal growth factor or transforming growth factor alpha. In surgical cases, all the gastric c arcinoma tissues and their adjacent normal mucosa expressed AR mRNA. I nterestingly, 20 (62.5%) out of 32 tumors expressed AR mRNA at higher levels than their corresponding normal mucosas (tumor/normal greater-t han-or-equal-to 1.2). No obvious correlation was observed between the AR mRNA levels and the histological types or tumor staging of gastric carcinoma. Immunohistochemically, AR protein was localized to the cyto plasm and/or nucleus in tumor cells. These results suggest that AR pro duced by tumor cells may be involved in the pathogenesis and/or progre ssion of human gastric carcinoma.