RETN and nasopharyngeal carcinoma: In analyzing the whole cell lysates from resistin-treated cells, we also found that blocking TLR4 activity via LPS-RS Ultrapure or siRNA transfection abolished the resistin-induced activation of p38 MAPK (Figure 4F,G), further proving that TLR4 was required for the resistin-induced activation of p38 MAPK in NPC cells.