MLLT1 and acute lymphoblastic leukemia: Recurrent chimeric protein fusions in T-ALL include rearrangements of KMT2A (AFDN (AF6), MLLT1, ELL), SET-NUP214, ABL1 (NUP214-ABL1, BCR-ABL1), MLLT10 (PICALM, DDX3X, NAP1L1, XPO1), and the ETS family (SPI and ETV6).