A recent study showed that an anti-human CD8α-targeted minibody (IAB22M2C) labeled with 64Cu specifically localized in orthotopic patient derived xenograft GBM tumors implanted in brain striatum of humanized mice; the PET signal in the tumor directly correlated with the number of human CD8+ cells that had trafficked into the tumors after systemic injection of human peripheral blood monocytes into the humanized mice41. The gene discussed is CD8A; the disease is neoplasm.