[Correlation between myeloperoxidase expression and gene alterations and prognosis in acute myeloid leukemia]

Objective: To analyze the percentage of myeloperoxidase (MPO)-positive acute myeloid leukemia (AML) blast cells, and to explore the correlation of MPO expression with the clinical features, gene alterations, therapeutic response and prognosis of AML. Methods: The expressions of MPO in BM blasts cells of 233 newly diagnosed AML were retrospectived analyzed, they were divided into two groups using the percentage of MPO-positive blast [low (≤70%) and high (>70%)], clinical features, gene alterations, chemotherapy efficacy and prognosis were compared between the two groups. Results: ①Of the 233 patients, 121(51.9%) were in the low MPO group, and the rest 112(48.1%) in the high MPO group. Favorable-risk group according NCCN guidelines of AML was always MPO-high (χ(2)=32.773, P<0.001), while MPO-low was closely related to poor-risk (χ(2)=7.078, P=0.008); ②DNMT3A mutation (χ(2)=6.905, P=0.009), spliceosome genes mutation (SF3B1/SRSF2/U2AF1) (χ(2)=5.246, P=0.022), RUNX1 mutation (χ(2)=4.577, P=0.032), ASXL1 mutation (χ(2)=7.951, P=0.005) and TP53 mutation (P=0.004) were more likely to be seen in the low MPO group, while C-KIT mutation (χ(2)=8.936, P=0.003) and CEBPA mutation (χ(2)=12.340, P<0.001) were more frequent in the high MPO group, especially CEBPA double mutation; ③The rates of first complete remission in the low MPO group were significantly lower than that in the high MPO group (38.8% vs 68.1%, χ(2)=15.197, P<0.001). Multivariate analysis showed that low MPO positivity significantly affected the CR(1) unfavourably. ④The overall survival (OS) and the progression-free survival (PFS) were significantly worse in the low MPO group (18.0% vs 89.4% for OS, and 11.5% vs 56.7% for PFS, P<0.001). Multivariate analysis disclosed that the low number of MPO was significantly unfavourable prognostic factor. ⑤The low MPO group still showed a worse survival even when restricted to the patients with normal karyotype, the OS and the PFS were 31.1% and 18.8% respectively. Conclusions: AML with different MPO expression percentage had a unique gene mutation spectrum. Low expression of MPO was an independent risk factor for CR(1), OS and PFS in AML patients, which may be a simple and highly significant factor for AML patients when evaluating the therapeutic efficacy and prognosis.