The Effect of the Injection of Heated Tumor Tissues on Resistance to Tumor Implantation

Abstract

In an earlier paper (1) it has been reported that destruction of growing tumors, or protection against subsequent implants, has resulted from the inoculation of animals with living homologous tumor cells (Flexner-Jobling rat carcinoma). Inoculation with tumor cells previously inactivated by heat, x-ray, radium, ultraviolet radiation, or chemicals, did not affect the growth of subsequent implants. Re-implantation of homologous tumor tissue (Rous chicken sarcoma) within a short period after the primary implantation did not affect the proliferation of the first or second implants (2), a result which indicates that different tumors vary in their power of inducing resistance. Our later study with the Flexner-Jobling rat carcinoma indicated that under the stated conditions of irradiation, the tumor regression and absorption following radium treatment conferred an immunity upon the treated animals (3). In that study it was observed that the tumor absorption following the action of very small doses of radon gave greater and more significant immunizing power than that following the action of large doses of radon. However, it was found that absorption of the irradiated tumor did not show any inhibiting influence upon the growth of a firmly established tumor located at a point away from the irradiated tumor.