HIF1A and neoplasm: Melatonin inhibitory effect on HIF-1 has been described mainly in the context of its anticancer action (Dai et al., 2008; Zhang et al., 2013; Paroni et al., 2014; Colombo et al., 2016; Prieto-Domínguez et al., 2017; Wang et al., 2017; Cheng et al., 2019), indicating melatonin’s potent role as a negative regulator of tumor-related angiogenesis.