R3327 adenocarcinoma of the Copenhagen rat as a model for the study of the immunologic aspects of prostate cancer.

The Dunning R3327 prostate adenocarcinoma of the Copenhagen rat was developed as a suitable model of human prostate cancer. Inoculation of tumor tissue mince or cells sc in the flanks of recipient rats produced tumors that had the macroscopic and microscopic characteristics of the human disease. The histologic picture of these tumors was that of a well-differentiated adenocarcinoma with the formation of glands and acid secretions within the acini. Tumors were also produced in the dorsolateral lobe of the prostate by the injection of cells. The intraprostate tumor, although initially confined to the injected lobe, grew to involve the surrounding tissues and eventually metastasized to the lymph nodes and lungs. Occasional metastatic lesions were found in other organs also. Acid phosphatase could be domonstrated by histochemical staining of frozen tumor sections, and elevated levels of the enzyme were seen in the sera of rats bearing long-term subcutaneous tumors. During investigation of the tumor, a fast-growing tumor line arose that grew equally as well in females as in males. The histology of this tumor was that of an undifferentiated anaplastic tumor.