IFNG and neoplasm: IFN-γ, a member of type II interferon, plays a key role in host defense and immune surveillance against microorganisms and tumor cells, primarily by acting as a potent activator of neutrophil and macrophage activities, promoting B-cell immunoglobulin isotype switching, promoting activation of CD8+ T-cells and differentiation of CD4+ T-cells towards a TH1 phenotype and, finally, up-regulates HLA class I expression and antigen presentation in tumor cells.