TGFB1 and nonpapillary renal cell carcinoma: Moreover, both TGF-β1-induced Snail signaling and the Jagged1-mediated Notch pathway can also promote the M2 polarization of the macrophage in the tumor microenvironment [61,62], and this means that DLK2-activated TGF-β1 and Notch signaling may participate in the M2 polarization of the macrophage in the ccRCC tumor microenvironment.