Tumor Control by Irradiation: A C3H/He Mouse Mammary Carcinoma in Mammary-Tumor-Agent-Positive and Mammary-Tumor-Agent-Free Mice

Summary

Tumor control assays have been described for studies of a C3H/He mouse mammary carcinoma transplanted into C3H/He (C3H/He × C57BL)F₁(C3BF₁), or (C57BL ×C3H/He)F₁(BC3F₁)animals. All irradiations were performed under conditions of local tissue hypoxia and at a tumor volume of 250 mm³. The TCD50 was the same for tumor growing in each of the three animal systems listed. Further, active immunization of the BC3F₁mice, by having tumor transplanted into the right thigh and then cured by local irradiation, did not affect the TCD50. Nor was the TCD50 modified by an active immunization procedure begun 21 days after application of local irradiation. Thus, in this animal tumor system, a very weak but readily demonstrable antigenicity of the tumor cells did not modify the tumor control probability after local irradiation of tumor.