CTLA4 and neoplasm: In recent years, immunotherapy for advanced stage OvCa was introduced in clinical trials using immune check points inhibitors targeting programmed cell death protein (PD1) and its ligand (PDL1) as well as cytotoxic T-lymphocyte-associated protein 4 (CTL4) with neutralizing antibodies that restore the functions of cytotoxic T-lymphocytes to recognize and eradicate tumor cells.