Immunocytochemical evidence for gastric proteases in adenocarcinoma of the stomach.

When anti-sera to bovine pepsinogen and chymosin (rennin) was used, immunoreactive tumor cells were found in 12 of 23 gastric adenocarcinomas irrespective of the tumor subtype, degree of differentiation, or the presence or absence of intestinal metaplasia in the adjacent gastric mucosa. Nine of ten lymph node metastases contained immunoreactive tumor cells. Except for focal positively staining acini in Brunner's glands the antibodies did not stain normal small intestine or areas of intestinal metaplasia. Although intestinal metaplasia is a predisposing factor in gastric carcinoma it may be irrelevant to its histogenesis and differentiation. Instead, the mucus neck cells, being the stem cells of the normal gastric mucosa, may be the target of malignant transformation in gastric carcinoma.