It was previously reported that the flavonoid kaempferol downregulated expression of G9a in gastric cancer cells (Kim et al., 2018) and studies in this laboratory reported that the flavonoids quercetin and kaempferol bind NR4A1 and downregulate G9a and other NR4A1-regulated genes in Rh30 cells (Shrestha et al., 2021) and similar results have now been observed for piperlongumine (Figure 7). This evidence concerns the gene NR4A1 and gastric cancer.