IFNG and neoplasm: IFN-γ is a key effector cytokine in immunity and upregulates major histocompatibility complex (MHC) molecules and the machinery involved in antigen processing and presentation.32 This upregulation of cell surface MHC class I by IFN- γ is essential for cytotoxic T cell activation, and thus, the host response to tumor cells.33 Granzyme B has long been known as a pro-apoptotic protease that is expressed by both cytotoxic lymphocytes and natural killer cells.