MAPK3 and hereditary clear cell renal cell carcinoma: Previous studies showed that leptin promoted viability and metastasis of renal cell carcinoma cells via activating the ERK1/2 and JAK/STAT3 signaling which could be partially abolished by ERK phosphorylation inhibitor U0126 and STAT3 phosphorylation inhibitor AG490, respectively (Li et al., 2008).