Relationship between biologic behavior and phenotypic expression in intramucosal gastric carcinomas.

We investigated the biologic behavior of gastric phenotype carcinoma of the stomach, especially in association with degradation of the extracellular matrix. One hundred fourteen lesions of intramucosal gastric carcinoma (IMGC) of differentiated type were studied. IMGCs were classified into 4 phenotypic categories--complete intestinal type (C type), incomplete intestinal type (I type), gastric type (G type), and unclassified type--through a combination of the expression of CD10, MUC2, HGM, and Con A. The expression of MMP-2, MMP-9, TIMP-2, and type IV collagen was investigated by immunohistochemical staining. The incidence of C-type IMGC, I-type IMGC, and G-type IMGC was 7.9%, 55.3%, and 36.8%, respectively. The incidence of positive MMP-9 expression in G-type IMGCs (57%) was significantly higher than that in C-type IMGCs (11%) or I-type IMGCs (35%) (P < .01). There was no significant correlation between phenotypes and expression of MMP-2, TIMP-2, or type IV collagen. There was a reverse correlation between the expression of type IV collagen and the expression of type IV collagenase (P < .001). In conclusion, gastric phenotype carcinomas have been shown to be highly invasive and metastatic, However, although they can potentially degrade the extracellular matrix via overexpression of MMPs compared with intestinal phenotype carcinoma, our data show no statistically significant separation of subtypes of intramucosal gastric cancer based on gross classification, histologic type, lymphatic or venous invasion, or lymph node metastases.