DNMT1 and gastric cancer: The decrease in intracellular methylation in MGC803 gastric cancer cells was supported by the author’s first report that casticin treatment drastically downregulated the mRNA and protein levels of “DNA methyltransferase 1” (DNMT1), whose gene family alteration causes aberrant methylation patterns responsible for tumor transformation and progression (Zhang and Xu, 2017) (Figure 4).