Markers of surface mucous cell type human gastric cancer cells: galactose oxidase-Schiff reactive mucins, monoclonal antibody SH-9 reactive mucins and cathepsin E.

Cellular differentiation of gastric cancer cells allows the classification of cell type into surface mucous cell, pyloric gland cell, intestinal absorptive cell and goblet cell types by mucin histochemistry and pepsinogen (Pg) immunohistochemistry. Surface mucous cell differentiation of gastric cancers of each histologic type has previously been detected by the galactose oxidase‐Schiff (GOS) reaction although this is not always positive in all cases. Mucus granules of surface mucous cells of normal gastric mucosa show an intense reactivity for SH‐9 (monoclonal antibody against CA125‐bearing antigenic molecule fragments). Cathepsin E is also expressed in the cytoplasm of surface mucous cells, weakly in absorptive cells of duodenal villi and occasionally in pyloric gland cells. Expression of SH‐9 reactive mucin and of cathepsin E were therefore investigated as possible additional markers to distinguish between the gastric cancer cell type in 203 primary stomach cancers. SH‐9 reactive mucin was found selectively in GOS positive cancer cells of surface mucous cell type and/or cancer cells unclassified by mocin histochemistry. These latter cells were therefore classified into the surface mucous cell category. Cathepsin E was found mainly in cancer cells of the GOS positive surface mucous cell type and occasionally, in intestinal absorptive and pyloric gland cell types. Galactose oxidase‐Schiff, SH‐9 and cathepsin E reactive or positive cancer cells were found in 145 (71.4%), 151 (74.4%) and 144 (70.9%), respectively, of the 203 primary stomach cancers investigated.