Interestingly, membrane TK1 seems to be found on the membrane of clinical samples of hematological malignancies like Burkitt's lymphoma, acute promyelocytic leukemia, acute T cell leukemia, and acute lymphoblastic leukemia and shown enzymatic activity, but not detectable in the normal resting or proliferating lymphocytes [46]. Here, TK1 is linked to T-cell acute lymphoblastic leukemia.