SMAD7 and melanoma: Another study focused on the activity of AA on the positive (Smad3) and negative (Smad7) transcription factors involved in the TGF-β1 downstream signaling [55]; AA was used as Smad7 inducer and was associated with naringenin, a Smad3 inhibitor, in order to effectively inhibit tumor growth in murine models of melanoma and lung carcinoma by inducing natural killer (NK) cells.