Ultrastructural localization of collagen type IV and laminin expression in the epithelial basement membrane of oral carcinomas

Epithelial basement membrane in oral carcinomas was examined by immunoelectron microscopy using anticollagen type IV and antilaminin antibodies. Intense and irregularly increased immunostaining was observed at the boundary between carcinoma cells and stromal tissue. Heterotopic immunostaining was found in the enlarged intercellular spaces of peripheral carcinoma cells. In addition, rough endoplasmic reticulum (rER) and vesicles in these cells were frequently stained. These findings suggest an increased synthesis and secretion of basement membrane components at the invading edge of the tumor, and also suggest that some oral carcinomas may spread into the surrounding tissue without apparent loss of the basement membrane.This study was presented in part at the 26th annual meeting of the Clinical Electron Microscopy Society of Japan, Kochi, October 6, 1994