TGFB1 and neoplasm: TGFβ signaling negatively regulates UCP2, as demonstrated in tumor cells where low malignancy levels suppress gene transcription by recruiting TGFβ-induced SMAD4 to six repressive SMAD-binding elements (RSBEs, − 100 to − 354) on the UCP2 promoter (Sayeed et al. 2010).