The Dunning tumors.

We have described the Dunning tumor, R3327, as a most useful model system in studies of human prostatic cancer. The tumor resembles the human disease in its histologic picture, ultrastructure, and most of its metastatic capabilities. The one exception to the latter is the apparent absence of metastatic lesions in the bone. Like the variability seen in human cancer of the prostate, the R3327 has been shown to develop multiple sublines, each with different histologic pictures, growth rate, and androgen dependence. Thus far the literature is replete with reports of the Dunning tumor as a model in hormonal, chemotherapeutic, and immunologic experiments. When we look at the results obtained in the five years since the Dunning tumor has been resurrected, we can be encouraged with what the future of prostatic cancer research holds with the use of this system.