We investigated the phosphorylation of smad2, smad3 and ERK1/2 in HK-2-TGF-b 1 (0.1)-PBMCs to investigate the signaling pathways that might be involved in the acceleration of TGF-b 1 -induced EMT on HK-2 cells by PBMCs. The phosphorylation of smad2 and smad3 was not detected (data not shown); however, the phosphorylation of ERK1/2 was detected in HK-2-TGF-b 1 (0.1)-PBMCs at 4 hrs and 12 hrs after co-culture by western blot analysis (Figure 7) . The phosphorylation of ERK1/2 Figure 9B ).