The author further tested GFP and CD19 dual-targeted human primary CD4+ and CD8+ T cells in a human xenograft two-tumor model using K562 as a target; they observed the selective clearance of CD19+GFP+ tumors rather than CD19+GFP− “bystander” tumors (serving as surrogate “healthy tissue”) in the same mice. Here, CD19 is linked to neoplasm.