NQO1 and neoplasm: Supporting the role of GARP in mediating the macrophage–tumor interaction, M1-like macrophages derived from GARP knockout mice (GARP KO M1) did not demonstrate the induction of methylation in the Nqo-1 gene by mouse KPC PDA cells comparing to wild-type M1-like macrophages (WT M1) (Fig. 4a).