IDO1 and neoplasm: Eicosanoids have been shown to modify the anti-tumor effects of cytotoxic T cells (DiMeo et al., 2008; Poczobutt et al., 2016b), alter the populations of innate immune cells to favor increases in immunosuppressive cells such as MDSC and tumor associated macrophages (Lone and Tasken, 2013; Esser-von Bieren, 2017), as well as modulating metabolic pathways such as IDO1 (Yang et al., 2001; Moore and Pidgeon, 2017).