While certain studies have demonstrated that TGFβ suppresses tumor growth and invasive capacity in the murine B16F1 melanoma model, contrasting evidence indicates that excessive inhibition of TGFβ signaling—either through overexpression of the inhibitory Smad7 protein or pharmacological blockade of type I receptor activity—attenuates melanoma cell invasiveness and diminishes metalloproteinase secretion. This evidence concerns the gene TGFB1 and neoplasm.