CTLA4 and Familial prostate cancer: An SV40 TAg transgenic model of prostate cancer [55] has been used to study the effects of combining blockade of cytotoxic T lymphocyte antigen 4 (CTLA-4) and vaccination with granulocyte macrophage colony stimulating factor (GM-CSF;Gvax) and subsequent derivatives of this vaccine strategy [56-60].