Immunohistochemical detection of metallothionein in carcinomatous and normal human gastric mucosa

Utilising a specific monoclonal mouse antibody (E9), metallothionein (MT) e xpression has been immunohistochemically investigated in 112 formalin-fixed paraffin-embedded surgical gastric samples, 38 of which were early carcino mas (EGC) and 74 advanced ones (AGC); clinico-pathological details and foll ow-up data (ranging from 3 to 197 months, mean 60.5 months) were available. Eighty-nine portions of gastric mucosa adjacent to examined carcinomas (tr ansitional mucosa) were also analysed; in addition, 22 biopsies of normal g astric mucosa were studied as tissue control. The MT immunoreactivity was e valuated by staining and intensity-distribution scores. A various MT positi vity was appreciable in the cytoplasm and nucleus of antrum or body gastric epithelial cells in 100% of normal control biopsies. 75/112 (67%) gastric carcinomas showed MT immunoreactivity with a significant lower expression i n AGC. No relationships were encountered between MT immunostaining and clin ico-pathological data; in addition, no difference in the Kaplan-Meier survi val curves of patients with Various MT expression was achieved. When the tr ansitional mucosa was examined, 84/89 (94%) samples were stained although t he immunoreaction was not always concordant with that encountered in adjace nt carcinomatous elements. The significant statistical decrease of MT score s observed by us moving from normal to neoplastic gastric mucosa allows us to exclude the hypothesis of an overexpression of MT in gastric carcinomas.