DNA histogram typing in human seminomas.

Characterization of the nuclear DNA content (DNA index and DNA histogram type) was carried out in 9 normal testicular tissues and 21 seminomas. Proliferative activity was further determined in the seminomas. Nuclear DNA content was assessed by means of a cell image processor computing the integrated optical density on Feulgen-stained nuclei from formalin-fixed paraffin-embedded materials. The results indicated that the so-called normal testicular tissues exhibited DNA histograms where three cell nuclei populations emerged in varying proportions. These three cell nuclei populations corresponded to haploid, diploid and tetraploid cell nuclei respectively. In contrast, most of the seminomas exhibited monomorphic DNA histogram patterns with a predominance of GO-G1 cell nuclei in the range of the 3c-4c nuclear DNA content. Further studies will be necessary in order to determine whether the DNA histogram has a predictive prognostic value or could be considered as a grading index.