DNMT1 and lung cancer: The lung cancer cell lines were treated with the DNA methyltransferase (DNMT) inhibitor 5-Aza-2′-deoxycytidine (AZA) at concentrations of 0, 0.5, 1.0, 1.5, 2.0, and 2.5 μM, and the SPOP expression levels were subsequently measured by qPCR and western blotting to further determine the DNA methylation effect on SPOP expression.