SCF activity on apoptosis inhibition in sarcoma cell lines. The evaluation was performed in serum-free conditions 24 hours after administration of exogenous SCF (0.5 μg/10⁶ cells). Each experiment was performed at least twice (mean of two reproducible experiments). Five of six (83%) of the cell lines showed an evident reduction in percentage of the apoptotic cells. (▦), SCF−; (▧), SCF+.