CTLA4 and plasmacytoma: Antagonist anti-CTLA-4 monoclonal antibodies exhibited antitumor properties in several murine tumor models, such as such as cancers of the ovary, bladder, brain, and fibrosarcoma, while CTLA-4 blockade was ineffective in B16 melanoma, SM1 mammary carcinoma, EL4 lymphoma, M109 lung cancer, and MOPC-315 plasmacytoma models [78].