This remains possible as such a blockade can upregulate B7 (Figs. 5 and 6), which could cause supra-stimulation of CD28, potentially causing T cell apoptosis.31,32 To address this issue, we killed tumor-bearing mice before the rejections were complete and analyzed the frequency of Treg cells in mice that received control Ig, Ipilimumab or L3D10. This evidence concerns the gene CD28 and neoplasm.