Tiacci et al. reported that in most cases of T-cell acute lymphoblastic anemia and AML, PAX5 was not expressed, while PAX5 was expressed in RUNX1-RUNX1T1–positive AML cases (15 of 42 (35.7%) AML cases with RUNX1- RUNX1T1). The gene discussed is PAX5; the disease is acute myeloid leukemia.