Dual-stain immunohistochemistry (IHC) of MAC2 and iNOS in control and olaparib-treated tumors confirmed a strong induction of iNOS expression by day 10 of treatment, consistent with the generation of an oxidative environment in which iNOS contributes to the oxidative burst of macrophages and their anti-tumor activity (Figures 3B and 3C). This evidence concerns the gene NOS2 and neoplasm.