On the mechanism of film neoplastogenesis.
Since the inception of experimental cancer research, all theories concerning the mechanism of transformation of normal cells into neoplastic cells were constructed on the basis of the postulate that interaction of an agent and cell constituents is a condition indispensable for the occurrence of the neoplastic transformation. In the course of the past three decades, however, all attempts to uncover agents responsible for the transformations induced by chemically inert films implanted in living tissues or for the "spontaneous" transformations in vitro in cell cultures devoid of added neoplastogens, yielded consistently negative results. In regard to the neoplastogenic effect of imbedded inert films, the present article takes into consideration that films implanted in living tissues hinder the circulation of interstitial fluid in their vicinity and as a result elicit anoxia and protracted low pH gradients in the environment of the cells adjacent to the films. The effects of such protracted low pH on the metabolic activities of the surviving cells are examined and a working hypothesis is offered concerning the role of protracted environmental low pH in the mechanism of film neoplastogenesis.