The initial level of MLL-partial tandem duplication affects the clinical outcomes in patients with acute myeloid leukemia.

This study aimed to analyze the effects of the initial MLL-partial tandem duplication (PTD) expression levels on clinical outcomes in 36 MLL-PTD-positive acute myeloid leukemia (AML) patients between 2014 and 2016. ROC curves showed 1.0% MLL-PTD as the optimal diagnostic cutoff for complete remission (CR). Nineteen and 17 cases had MLL-PTD <1.0% (low-level group) and ≥1.0% (high-level group), respectively. The FAB type distribution (M2 incidence, 100% vs. 53%, p = .003) and double-CEBPA-mutation incidence (37% vs. 0%, p = .008) significantly differed between the groups, as did the CR rates after the first (78.9% vs. 35.3%, p = .008) and second chemotherapies (84.2% vs. 47.1%, p = .001). High MLL-PTD level was the only independent factor affecting the CR rate (odds ratio = 0.16, p = .024). The 24-month overall survival was significantly lower in the high-level group (52.6% vs. 29.4%, p = .043). In conclusion, AML patients with high initial MLL-PTD levels have lower induction CR and survival rates.