DNA ploidy pattern and cell cycle stage of tumor cells in soft-tissue sarcomas: clinical implications

Staining and counting of argyrophilic nucleolar organizer region (AgNOR), segments of DNA with ribosomal genes, is useful for estimation of the proliferative activity in soft tissue sarcoma (STS). The precise role of AgNOR in STS, however, is still uncertain. In the present study, ploidy pattern and stage of cell cycle were analyzed in 151 cases of STS in the extremities and trunk, and their correlation with AgNOR and utility as independent prognostic factors were estimated. For this, microspectrophotometric and flow-cytometric analyses were done on paraffin-embedded material from 84 and 111 cases, respectively. Fifty-five percent cases showed an aneuploid pattern with a less favorable prognosis. The range of the DNA index and percentage of cells in S + G2M phase were 0.89-2.04 (mean +/- SD, 1.23 +/- 0.32) and 5.4-83.7% (mean +/- SD, 32.95 +/- 17.92), respectively. Tumors having less than 40% cells in the S + G2M phase showed a favorable prognosis compared to those over 40%. Both the ploidy pattern and stage of the cell cycle showed a good correlation with the AgNOR count: a high frequency of cases having aneuploidy and S + G2M phase in the AgNOR high count group. These findings provide a theoretical base for explaining the utility of AgNOR for the estimation of proliferative activity. In multivariate analysis, only AgNOR counts were a prognostic factor among histologic factors reflecting proliferative activity of tumors. The DNA ploidy pattern and the stage of the cell cycle was proved not to be an independent factor for prognosis.