The nature of host tissue destruction in tumor invasion

Abstract

The nature of host tissue destruction in tumor invasion was investigated in experimentally induced carcinomas and sarcomas, xenografted into skeletal muscle. By means of light and electron microscopy it was shown that in both carcinomas and sarcomas the confrontation of host tissue with the invading tumor cells does not result in immediate destruction of host tissue but in a transitory state of coexistence which gradually proceeds to progressive host tissue atrophy. This process of progressive atrophy, which finally results in the total disappearance of the invaded host tissue, is considered to be caused mainly by the increasing pressure and competitive withdrawal of oxygen and nutrients by the invading and proliferating tumor cells. Morphological changes suggesting an active enzymatic breakdown of host tissue cells by tumor cells were not observed during any stage of tumor invasion.