SMAD2 and neoplasm: Indeed, TGF-β is directly involved in CD103 expression in tumor-specific T cells upon engagement of TCR with specific tumor peptide–MHC-I complexes (7), through binding of Smad2/3 and NFAT-1 transcription factors to promoter and enhancer elements of the ITGAE gene, which encodes the CD103 (αE) subunit (29).