Treatment with PMA/TGF-β caused growth suppression in RL but not in DB cells. Lymphoma cells were plated at 0.125 × 10⁶ cells/mL and treated with either medium alone, PMA (0.15 ng/mL), or PMA/TGF-β (10 ng/mL) at various time periods. At the end of each time point, cell counts were performed. Results are representative of 3 experiments.