DNA flow cytometry in carcinoma of the prostate for diagnosis, prognosis and study of tumor biology.

Flow cytometry has been used to measure the cellular DNA content in fine-needle aspirates of a large number of patients with untreated prostate carcinomas. The tumors were subdivided into diploid, tetraploid aneuploid and non-tetraploid aneuploid with one or several aneuploid cell populations. The clinical relevance of this subdivision is supported by studies of the metastatic potential of the tumors and the outcome of the disease by follow-up of the patients. Changes were found in the proportion of the various ploidy classes with tumor stage. These were typical for the behavior of a 3-compartment system. Thus, the proportion of diploid tumors decreased exponentially with stage, that of the tetraploid-aneuploid tumors increased to maximum at intermediate stages, while the non-tetraploid aneuploid tumors increased exponentially after some delay. This strongly supports the concept of a continuous development of the prostate carcinoma from low grade to high grade connected with the doubling of the near-diploid genome of the tumor, and followed by successive loss of chromosomes from the near-tetraploid tumor. Further support of this concept is gained by the study of repeated fine-needle aspirates and the observation of coexisting diploid and aneuploid cell populations in the developing tumor. Clinical consequences of this concept are discussed.