SMAD3 and nasopharyngeal carcinoma: In nasopharyngeal carcinoma, the EBV-EBNA1 molecular mechanism is identified as a potent stimulator of chemotactic migration of Tregs toward the TME via upregulation of the TGF-β1-SMAD3 (mothers against decapentaplegic homolog 3)-PI3K-AKT-c-JUN-CXCL12 (C-X-C motif chemokine 12)-CXCR4 (C-X-C chemokine receptor type 4) axis and downregulation of miR-200a.