Additional sex combs like 1 (ASXL1) mutations are one of the most common molecular biological abnormalities in patients with primary myelofibrosis (PMF), and the effect of these mutations on prognosis remains controversial. Hence, we conducted a meta-analysis to assess the prognostic value and clinical characteristics of ASXL1 mutations in PMF patients. Eligible studies were systematically searched from PubMed, Embase, and the Cochrane Library. We extracted the hazard ratios (HRs) and their 95% confidence intervals (CIs) of overall survival (OS) and leukemia-free survival (LFS), the number of patients transformed to acute leukemia, and clinical characteristics to carry out a meta-analysis by fixed effect model or random effect model according to the heterogeneity between studies. A total of 4501 PMF patients from 16 cohorts of 14 studies were included in this meta-analysis. The results revealed that ASXL1 mutations might predict a shorter OS (HR = 2.30, 95% CI: 1.79–2.94, P < 0.00001) and a higher probability of transformation to acute leukemia (LFS: HR = 1.77, 95% CI: 1.30–2.42, P = 0.0003; the rate of acute leukemia transformation: OR = 2.06, 95% CI: 1.50–2.83, P < 0.00001). Furthermore, ASXL1 mutations were correlated with patients older than 65 years old, male, a lower level of platelet counts, and a higher risk of the international prognostic score system. These findings indicate that ASXL1 mutations have a significant adverse impact on the prognosis of PMF patients and may contribute to risk stratification and prognostic assessment for PMF patients.

To assess the effects between MPL and JAK2V617F on the thrombosis risk and peripheral blood cell counts in patients with essential thrombocythemia (ET), we identified eligible studies from PubMed, Embase, and the Cochrane Library. Seven studies were ultimately included in this meta-analysis. All studies reported the peripheral blood cell counts of ET patients, and three of them reported the eligible thrombotic events. In comparing the effect of MPL versus JAK2V617F on thrombosis, 1257 ET patients (73 MPL + and 1184 JAK2V617F +) were included. MPL-positive (MPL +) ET patients had a higher risk of thrombosis than JAK2V617F-positive (JAK2V617F +) ET patients [RR = 1.80 (1.08–3.01), P = 0.025]. And 3453 ET patients (138 MPL + and 3315 JAK2V617F +) were included in the comparison of peripheral blood cell counts. Platelet counts of MPL + ET patients were higher than that of JAK2V617F + ET patients [WMD = 81.18 (31.77–130.60), P = 0.001]. MPL + ET patients had lower hemoglobin [WMD =  − 11.66 (− 14.32 to − 9.00), P = 0.000] and white blood cell counts [WMD =  − 1.01 (− 1.47 to − 0.56), P = 0.000] than JAK2V617F + ET patients. These findings indicate that the MPL mutation is a high-risk factor for thrombosis in ET patients, and it may be rational to include MPL mutation in the revised IPSET as a criterion for thrombosis prediction scores. And given the differences in peripheral blood, it is necessary to further study whether MPL + ET patients differ from JAK2V617F + ET patients in bleeding and survival.

No abstract