NR4A1 and cancer: In cancer cells inverse NR4A1 agonists decrease cancer cell growth, induce apoptosis and inhibit migration/invasion (Lee et al., 2014a; Safe et al., 2021) and treatment of RKO, SW480 and HCT116 cells with 7.5 and 15 μM piperlongumine inhibited cell growth (Figures 2A–C) as determined in an XTT assay.