MUC13 and nonpapillary renal cell carcinoma: Although the mechanisms of MUC3A and MUC13 in the carcinogenesis and progression of ccRCC have not been investigated, it has been shown that the expression of MUC3A might be controlled through the PKC signaling pathway, which regulates the metastatic invasiveness of tumor [83]; MUC3A overexpression is linked with the reduction of tumor suppressor gene p53 and activation of critical oncogenes HER2, PAK1, ERK, and Akt [84].