Given the apparently low therapeutic index of HDACis with associated toxicity, and considering our initial observation of the increased expression of HDAC8 characteristically in MSC-MPN JAK2V617F, we decided to further investigate the role that HDAC8 could have in the biology of MSC from MPN patients and later on the effects of HDAC8 inhibition on the behavior of MSC-MPN by using a specific inhibitor PCI34051. The gene discussed is HDAC8; the disease is myeloproliferative neoplasm.