HHEX and acute lymphoblastic leukemia: Meanwhile, T-ALL is classified into four main subtypes according to the characteristic oncogenic aberrations, namely TLX (TLX3 rearrangements or HOXA activating events), TLX1/NKX2.1 (LTX1 or NKX2.1 rearrangements), TAL/LMO (high expression of TAL1, TAL2, LMO1/2/3), and early thymocyte progenitor (ETP) /immature-ALL (high expression of LMO2, LYL1, HHEX, and BCL2) [10,13].