Preclinical studies have reported that the combination of CTLA-4 blockade and a vaccine composed of granulocyte–macrophage colony-stimulating factor (GM-CSF)-expressing tumor cells (GVAX) resulted in regression of parental mammary carcinoma or melanoma or prostate cancer cells [52,54], while each treatment alone was ineffective. This evidence concerns the gene CTLA4 and breast carcinoma.