DNA flow analysis of soft tissue tumors.

The cellular DNA content of 81 soft tissue tumors was determined by means of flow cytometry and related to conventional histologic classification of the same tumors. Comparison of histologic and cytometric analysis showed that all 23 benign tumors were diploid (normal DNA content), whereas the malignant group included both diploid and aneuploid (abnormal DNA content) lesions. There appeared to be a relationship between tumor grade and ploidy level in that 92% of Grade II, 28% of Grade III, and 11% of Grade IV lesions were diploid. Cell distribution analysis, feasible in 51 cases, disclosed that diploid lesions had a low proportion of S and G2 + M cells and most aneuploid lesions a high proportion, indicating a relationship between ploidy level and proliferative activity. The current study shows that solid mesenchymal tumors may be analyzed by DNA flow cytometry. Regardless of histogenetic type, it appears that benign and low-grade tumors are diploid and high-grade tumors, in general, are aneuploid. As to exceptions, DNA analysis may prove to give information beyond that obtained by subjective histologic interpretation. Thus, adequate follow-up might show that high-grade lesions with a diploid DNA content are associated with a better prognosis than expected from histologic classification.