Thus, our data unambiguously demonstrate that the presence of high SKI levels is compatible with active TGF-β signaling, implying that high SKI staining in tumors may not be an indication of an absence of TGF-β-driven disease progression, as exemplified by studies with inhibitors of the TGF-β pathway that efficiently prevent melanoma tumorigenesis and metastasis [36-38]. Here, TGFB1 is linked to melanoma.