The Internal Milieu of Tumors

Abstract

Neoplastic cells in vivo are part of an organized structure and exist in a milieu consisting of at least 2 compartments, the vascular system and the interstitial space. Nothing can reach tumor cells without passing through these compartments, and the neoplastic cells can survive only as long as both compartments are able to maintain a physiological milieu. It is reasonable to believe that the ability to influence effectively the biological properties of neoplastic cells in vivo would be enhanced if more were known about the internal milieu of tumors. The experiments performed showed that it is possible to estimate the volume of the 2 compartments; to measure the blood flow through the tumor and to increase or decrease this flow; to sample the interstitial fluid and to compare its composition with that of other body fluids; to determine the production of collagen and to assess the role played by neoplastic cells in this production; and to evaluate the acid-base status of the interstitial fluid and to induce changes specifically in this fluid.