STAT3 and nonpapillary renal cell carcinoma: We found that overexpression of TTC13 enhanced, while TTC13 knockdown inhibited, the expression of β-catenin, p-JAK-2 and p-STAT3 in ccRCC cells, suggesting the regulation of TTC13 in Wnt/β-catenin and IL6-JAK-STAT3 pathways (Fig. 4D).