Moreover, TGF-β1-EMT axis (Smad-dependent) through TβRII is supposed to play an important role in the in vitro induction of one of sphere-forming CSC-like populations in RCC and in associated in vivo sarcomatoid de-differentiation within xenografts derived from these tumor spheres [59]. This evidence concerns the gene TGFB1 and renal cell carcinoma.