Activating JAK2 V617F mutation is present in many patients with chronic myeloproliferative neoplasms. We evaluated, retrospectively, clinical and laboratory data from 70 patients with BCR-ABL1 negative, JAK2 positive, chronic myeloproliferative disease. Quantity of the JAK2 mutant allele was tested for correlation with the clinical presentation, type of chronic myeloproliferative disease, hemog...