An experimental model for studying radiation-induced suppression of antitumor resistance

In experiments on mice (CBA × C57Bl)F 1 an experimental model is developed for studying the effect of radiation on antitumor resistance. Adequate ways are offered for statistical processing of the data on enhancement of tumor growth in the irradiated organism. The validated model is a solid tumor developing after inoculation of a mouse with 1000 cells of Ehrlich ascites tumor into a hind shin, combined with suppression of antitumor resistance upon a 6-Gy ( 137 Cs) whole-body exposure. The recommended parameters for assessing tumor growth are: share of animals with tumors by day 30 after inoculation, length of the latent period, probability of tumor development, and tumor volume by day 30. For data processing, besides the common Fisher, χ 2 and Mann-Whitney tests, we recommend the Kaplan-Meier method and Log-rank. The proposed model can be a reliable tool in solving problems at the junction of radiobiology, oncology, immunology, pharmacology, etc.