Targeting solely mismatched tumor mHags boosts the GVT effect. HLA-matched patients and donors remain mismatched for multiple mHags. According to our working hypothesis, host-derived antigen presenting cells (APCs) persisting after allogeneic SCT induce an antihost response of donor T cells. Based on the mHag tissue distribution, the antihost response is dissected into a branch mediating only GVT effects and a branch mediating both GVT effects and GVHD. Our findings indicate that immunotherapy targeting only mismatched tumor mHags is sufficient to boost the GVT effect.