Objective To investigate the relationship of the mutation frequency and type of JAK2 exon 12and 14 with myeloproliferative neoplasm(MPN)subtype and myelodysplastic syndrome(MDS)in patients with MPN and MDS.Methods Genomic DNA was extracted with DNA extraction kit from the peripheral blood leukocytes of 104 patients with MPN(MPN group),12 patients with MDS(MDS group)and 20 healthy volunteers(control group).JAK2 exon 12and14were analyzed by direct sequencing and the mutation rates of various MPN subtypes were...