KORs are currently being investigated as a therapeutic target for the treatment of pain because KOR activation has potent anti-nociceptive effects in various models of acute (mechanical, thermal and chemical) (Briggs et al., 1998; Beck et al., 2019; Escudero Lara et al., 2021), inflammatory (Paton et al., 2017), neuropathic (Sounvoravong et al., 2004), and cancer pain (Edwards et al., 2018). The gene discussed is OPRK1; the disease is cancer.