RESUMO
PURPOSE: Chronic neutrophilic leukemia is a rare form of myeloproliferative neoplasm characterized by mature neutrophil hyperleukocytosis. The majority of patients harbor somatic mutations of CSF3R gene and are potentially amenable to targeted therapy with JAK inhibitors. The incidence and clinical significance of additional mutations requires clarification. MATERIALS AND METHODS: A next-generation sequencing approach for myeloid malignancy-associated mutations was applied to diagnostic and matched blast crisis samples from four chronic neutrophilic leukemia patients. RESULTS: Next-generation sequencing confirmed the CSF3R T618I in all patients with identification of concurrent SRSF2, SETBP1, NRAS and CBL mutations at diagnosis. At blast crisis, clonal evolution was evidenced by an increased CSF3R T618I allele frequency and by loss or acquisition of CBL and NRAS mutations. CONCLUSION: The diagnostic utility of a targeted next-generation sequencing approach was clearly demonstrated with the identification of additional mutations providing the potential for therapeutic stratification of chronic neutrophilic leukemia patients.