Here, we analyzed EZH2 expression and its association with tumor proliferation and signaling cascade molecules in 43 ATLL cases and a total of 103 cases of other types of T-cell lymphomas, including T-ALL, ALCL-ALK+, ALCL-ALK−, NK/TCL, PTCL-NOS, AITL, and T-PLL. Here, EZH2 is linked to adult T-cell leukemia/lymphoma.