Phospho-STAT5 Immunostains as a Surrogate Marker for JAK2 V617F Mutations in non-CML Chronic Myeloproliferative Disorders

Newsletter by Rodney T. Miller, M.D., Director of Immunohistochemistry ProPath Laboratory

"Chronic myeloproliferative disorders (CMPD) encompass a variety of entities, including chronic myelogenous leukemia (CML), polycythemia vera (PV), essential thrombocythemia (ET), and chronic idiopathic myelofibrosis (CIMF). For many years, it has been known that CML is associated with a specific chromosomal abnormality, the t(9;22)(q34;q11), resulting in an abnormal BCR/ABL1 fusion gene. More recently, a number of studies have found that roughly 80% of PV patients, 38% of ET patients, and 46% of CIMF patients harbor a specific mutation involving the JAK2 gene, where the normal valine present at residue 617 is replaced by phenylalanine (JAK2 V617F mutation). This month, we call attention to an article published in the February 2007 edition of The American Journal of Surgical Pathology, that describes results of a study performed at the Cleveland Clinic involving the use of antibodies to phosphorylated STAT5 (pSTAT5) as a surrogate marker of the JAK2 V617F mutation."