The JAK2 V617F mutation is a single nucleotide change that substitutes valine (V) with phenylalanine (F) at position 617 in the JAK2 protein. This mutation activates the JAK-STAT pathway independently of external signals, leading to excessive cell division and survival. It is present in about 95% of patients with polycythemia vera and in a significant proportion of patients with other MPNs.
