Therefore, in order to study whether the demethylation drugs arsenic trioxide and 5-azacitidine can affect the growth activity of tumor cells by regulating the TGF-β signaling pathway, we used qRT-PCR to study the effects of arsenic trioxide and 5-azacitidine on the TGF-β signaling pathway, and the results showed that arsenic trioxide and 5-azacitidine can significantly promote the expression of the TGF-β, Smad2, Smad3, and Smad4 (Figures 4(c)–4(f)). The gene discussed is SMAD3; the disease is neoplasm.