Non‐driver gene mutation analysis in a large cohort of polycythemia vera and essential thrombocythemia

Objectives A proportion of patients with polycythemia vera (PV) and essential thrombocythemia (ET) harbor non‐driver mutations associated with poor prognosis. In this study, we analyzed the frequency of non‐driver mutations in a large Japanese PV and ET cohort. Furthermore, we studied the relationship of these mutations and prognosis in Japanese patients. Methods We enrolled 843 Japanese patients with PV or ET. Non‐driver mutations were analyzed by target resequencing using next‐generation sequencing. The association of the mutations with the prognosis was estimated using multivariable logistic regression analysis and log‐rank test. Results Non‐driver mutations were detected in 31.1% and 24.5% patients with PV and ET, respectively. Among them, ASXL1 mutations were identified as a risk factor for leukemic/myelofibrotic transformation in PV and ET patients (hazard ratio: 4.68, p = .006). The higher‐risk groups of the mutation‐enhanced international prognostic system (MIPSS)‐PV and MIPSS‐ET incorporating non‐driver mutations exhibited significantly shorter overall survival compared with the low‐risk group (p