Distribution of Transforming Growth Factor‐β and Its Receptors in Gastric Carcinoma Tissue

The distribution of the three mammalian isoforms of transforming growth factor (TGF)‐β (TGF‐β1,‐β2, and ‐β3) as well as their signaling receptors, TGF‐β type I and type II receptors (TβR‐I and TβR‐II, respectively), in gastric carcinoma tissue was examined by immunohistochemistry using specific antibodies. Tissue specimens were obtained from 25 cases of gastric carcinoma, which were classified into two groups according to Lauren's classification, i.e. 15 cases of diffuse carcinoma and 10 cases of intestinal carcinoma. In normal gastric mucosa apart from carcinoma nests, all of TGF‐β1, ‐β2, ‐β3, TβR‐I and TβR‐II were clearly demonstrated in fundic glands. In sharp contrast, none of them was detectable in surface mucous cells. In carcinoma cells, strong staining for TGF‐β1, ‐β2 and β3 was obtained only in diffuse‐type carcinoma. In particular, carcinoma cells scattered as single cells or small nests had a tendency to show strong staining for TGF‐βs. The receptors tended to be distributed concomitantly with the ligands, and diffuse‐type carcinoma showed stronger receptor staining than intestinal‐type carcinoma. In cancer stroma, TGF‐βs and receptors were detected in both diffuse and intestinal types, but the area with positive staining was wider and more dispersed in diffuse‐type carcinoma than in intestinal carcinoma. These results suggest that TGF‐β may contribute in part to the variety of histogenesis and mode of progression of gastric carcinoma.