While the occurrence of GPR56, CD53 and CD59a on leukemia cells is known31–36, GPR56, CD53 and CD59a are highly expressed in the thymocytes of Lck-Lmo2 mice relative to wild type thymocytes (Fig. 8A–C) and are also on the overt human tumors in addition to CD7. This evidence concerns the gene CD53 and leukemia.