SMAD7 is an antagonist of TGF-β signaling that functions as a negative regulator of multiple inflammatory and fibrotic pathways. As an I-SMAD family member, SMAD7 inhibits TGF-β receptor signaling by preventing SMAD2/3 phosphorylation through receptor blockade and recruitment of protein phosphatase complexes 12. Beyond canonical TGF-β antagonism, SMAD7 regulates NF-κB pathway activation and promotes autophagic flux through TFEB-mediated transcription 34. SMAD7 expression is epigenetically controlled and can be suppressed by HDAC5-MEF2A interactions, with implications for fibrotic disease development 2. Clinically, SMAD7 polymorphisms associate with colorectal cancer susceptibility, particularly the rs11874392 variant which increases risk in females and individuals with smoking/drinking histories 5. Therapeutically, SMAD7 shows promise in immunotherapy: CAR-T cells coexpressing SMAD7 demonstrate enhanced persistence, reduced exhaustion, and decreased inflammatory cytokine production in solid tumors 6. SMAD7 dysregulation contributes to pathogenic processes in rheumatoid arthritis, intrauterine adhesions, bladder cancer metastasis, and intervertebral disc degeneration through TGF-β pathway activation and altered cell fate transitions 7489.