Structural studies on initial lymphatics adjacent to gastric and colonic malignant neoplasms

Invasion and metastases are the main causes of death from cancer, and progn osis is best correlated with invasion of malignant cells into initial lymph atics and dissemination to regional lymph nodes. Using both light and trans mission electron microscopy, we examined human gastric and colonic cancers and their relation to initial lymphatics. Invasion of malignant tumor cells into the initial lymphatics was characterized by interdigitating and overl apping endothelium giving way to open junctions as lymphatic endothelial ce lls were apparently dissolved and destroyed. Cytoplasmic vesicles, mitochon dria, and rough endoplasmic reticulum were qualitatively increased as demon strated by image analysis.