Immunohistochemical studies of basement membrane components in primary and metastatic lesions of early gastric cancer.

The basement membrane components in the primary and metastatic lesions of 29 cases of early gastric cancer were histologically and immunohistochemically examined. On silver-impregnated specimens, reticular fibers were much more abundant in the basement membrane regions and stromal tissues in the metastatic lesions than in the primary lesions. Immunohistochemically, the basement membrane components examined, i.e. laminin, type IV collagen and fibronectin were localized much more intensely in the basement membrane and more diffusely in the stroma in the differentiated adenocarcinomas than in the undifferentiated adenocarcinomas, having a closer relationship with the rate of proliferation of reticular fibers in the differentiated adenocarcinomas than in the undifferentiated ones. Electron microscopically, laminin was also detected in the endoplasmic reticulum of differentiated adenocarcinoma cells. From these results it should be noted that the metastatic mechanism in the differentiated adenocarcinomas may be different from that in the undifferentiated adenocarcinomas of the stomach from the viewpoint of the localization pattern of basement membrane components.