KLF4 and cancer: First, we confirmed that COX2 activity can change the expression of some of the genes we have identified as COX2-target or effector genes in human cancer (Stamatakis et al., 2015; Jiménez-Martínez et al., 2019; Jiménez-Segovia et al., 2019; Hidalgo-Estévez et al., 2020), namely, Ptge2, Ptges, Dusp10, Pmepa1, Inhba, Il15, and Nfkbia. There was also a tendency for Klf4, Tacstd2, Nfat5, Tgfb1, and Il15ra to be upregulated with COX2 overexpression in CT26 cells, as it happened in HT29 human cells, but without reaching statistical significance.