It is also known that myeloperoxidase (MPO) and NADPH oxidase are enzymes that play a vital role in the induction of IFN-γ by monocytes and in the killing and phagocytosis of microorganisms through the production of ROS by neutrophils and that these enzymes are iron-dependent, and that their catalytic activity is inhibited by ID, leading to impaired phagocytosis, reduced bactericidal activity, and induced tumor emergence (99, 100). This evidence concerns the gene MPO and neoplasm.