In another Philadelphia chromosome-negative MPN cohort study, Schmidt et al. [103], by quantifying in vitro NETs induced by the treatment of neutrophils with ionomycin, showed: (1) a clearly higher level of NET formation in MPN patients than in healthy donors; (2) positive correlation between somatic mutations in the JAK2 V617F and CALR genes and increased NET formation; and (3) that NET formation is not linked to either thrombosis or to classical risk factors for thromboembolic complications. The gene discussed is CALR; the disease is myeloproliferative neoplasm.