Tumor biology in diagnostic cytology: DNA cytometry in carcinomas of the bladder and prostate.

Quantitative measurements of nuclear DNA by flow cytometry have been used in the investigation of bladder and prostate carcinomas. The subdivision of tumors into diploid, tetraploid and aneuploid enables further characterization of morphologically defined tumors. Distinct differences in the distributions of ploidy of aneuploid grade 2 and grade 3 bladder carcinomas strongly suggest two different pathways of development of these gross chromosomally abnormal tumors. Significantly lower S-phase values of grade 2 tumors compared with grade 3 tumors of the same degree of ploidy enable the differentiation of these two tumor types. The proportion of S-phase cells is significantly related with the stage of invasiveness of bladder carcinomas. In prostate carcinomas, the exponential decrease of diploid tumor with tumor stage, the increase of tetraploid tumors to maximum at intermediate stages, and the exponential increase of aneuploid tumors with stages after some delay strongly support the concept of the continuous development of the prostate carcinoma according to a three-compartment system. Further support for this concept is gained by the study of repeated fine-needle aspirates of the tumor and the observation of coexisting diploid and aneuploid cell lines in the developing tumor. An adverse effect of hormone deprivation on composed tumors by elimination of androgen-dependent and outgrowth of androgen-independent cell lines cannot be excluded.