Development and application of a rat tumor model for human bronchial carcinoma

Five squamous cell carcinomas were induced in the lungs of WAG/Rij rats by radiation emitted from isotopes iridium-192 or iodine-125. Tumor fragments were transplanted subcutaneously in syngeneic hosts for propagation of the tumors. A lung cancer model based on implantation of tumor fragments in the lung has been developed. Tumor implants in the lung grew into large invasive squamous cell carcinomas. Metastases in the renal cortex were frequently observed. Tumor growth was determined from repeated chest radiographs. Volume changes after cytostatic treatment could be monitored accurately up to several months. Squamous cell carcinomas transplanted subcutaneously responded as heterogeneously to a variety of cytostatic drugs as did their human counterparts. Responses of the tumor line L17 to doxorubicin were similar when tumors were growing intrapulmonarily or subcutaneously. However, the response of L33 tumors to cisplatin was different, depending on the location. The tumors growing in the lungs provide a model for realistic testing of regimens involving radiation doses, cytostatic drugs, and combinations thereof.