NOTCH1 and acute lymphoblastic leukemia: The weaker TM/RAM epitope expression of the three ATL- and HTLV-1-infected T-cell lines than that of HD-Mar before incubation with GSI (Fig. 3) suggests a protein structural basis, and NOTCH1 signaling is much more important for the progression of T-ALL with t (9;14) than ATL without a PEST domain mutation.