The clinical importance of DNA synthesis and aneuploidy in bone and soft tissue tumours.

DNA flow cytometric analysis including the analysis of S-phase fraction was performed on 46 bone and soft tissue tumours. Histologically, 24 lesions were benign, 11 were low grade and 11 were high grade malignant tumours. The percentages of aneuploidy in these groups were 29, 54 and 82, respectively. The S-phase fraction was smaller than 14% in all benign tumours. High S-phase fraction (> or = 14%) was found in 3 out of 11 low-grade tumours (27%) and in 9 out 11 high-grade tumours (82%). Seven of nine patients who died of metastatic disease during the average 5 year follow-up had aneuploid stemlines with S-phase fraction higher than 14%. Histologically, these were all high-grade tumours. Three patients with high S-phase in low-grade tumours survived. We conclude that high DNA synthetic activity in an aneuploid population, more than the DNA aneuploidy alone, has prognostic significance in musculoskeletal tumours.