JAK2 and myeloproliferative neoplasm: These findings are in agreement with the study of Nielsen et al., who showed that the JAK2 V617F mutation burden level was associated with MPN disease development and progression rate, consistent with a biological continuum of increasing the JAK2 V617F allele burden across the growing severity of myeloproliferative neoplasm from no disease through ET and PV to PMF [26].