ACTA1 and nonpapillary renal cell carcinoma: On the other hand, even though the expression of α-SMA contributes to EMT in normal epithelial cells during embryogenesis and wound healing [74], and also in certain cancers [20], no change in the expression of α-SMA between primary tumours versus normal kidney tissues; and between metastatic and primary tumours; and in different stages of ccRCC indicates that α-SMA may not have an active role in EMT-induced cancer progression in ccRCC.