One of the most common types of mutation of JAK2 is the V617F, a somatic gain-of-function mutation that changes the 1849th coding nucleotide from guanine (G) to thymine (T) resulting in a replacement of amino acid from valine to phenylalanine (c.1849G > T, p. Val617Phe), which is strongly associated with MPN. This evidence concerns the gene JAK2 and myeloproliferative neoplasm.