IFNG and pancreatic neoplasm: The mathematical model of the tumor-immune system of this study is constructed using ODEs to describe the dynamics of interactions between pancreatic cancer cells and major innate and adaptive immune system components includes cytotoxic T lymphocytes (CTLs), natural killer (NK) cells, myeloid-derived suppressor cells (MDSCs), TCD4+ cells (T helper), T regulatory cells (Tregs) and cytokines e.g. interleukin-2 (IL-2), interferon-gamma (IFN-γ) and transforming growth factor-beta (TGF-β).