TISSUE-CULTURE LOSS OF ANEUPLOID CELLS FROM CARCINOMAS OF THE PROSTATE

The frequency of aneuploid cells in cultured prostate carcinoma specim ens was investigated. Ploidy distribution of the original tissue was e stablished by flow cytometry (FCM). Fluorescence in situ hybridization (FISH) of chromosome I was applied to directly isolated and cultured cells to investigate whether any modifications in the ploidy distribut ion of chromosome I took place during tissue culture. In six tumor spe cimens that were diploid by FCM and FISH, no differences were found in the ploidy distribution of chromosome I before and after tissue cultu re. In eight tumors that were aneuploid by FISH, the percentage of ane uploid nuclei was significantly reduced from 28.0 +/- 15.0 (range 13-5 9%) in uncultured cells to 9.1 +/- 4.4 (range 4-18%) after tissue cult ure. The reduction of aneuploid nuclei ranged from 44 to 85%, which me ans that the majority of the aneuploid cell populations that were obse rved in the original specimens were undetectable in cultured samples. This suggests a preferential growth of normal epithelial cells. The da ta presented can explain the high percentage of diploid karyotypes usu ally found in short-term cultured prostate carcinoma specimens. (C) 19 93 Wiley-Liss, Inc.