CTLA4-T cells efficiently lysed CD80-positive or CD86-positive tumor cells (Raji, RL, and NALM6), but not CD80/CD86-negative K562 cells, whereas control effector cells (GFP-T) could not initiate specific lysis on either cell line (Figure 1E and Supplementary Figure 1C). Here, CTLA4 is linked to neoplasm.