Seven Cases of JAK2 Mutation Negative Chronic Polycythemia Patients with Elevated IGF-1R

Abstract

We previously reported that assaying blood MNC (Mononuclear cells) IGF-1 levels by Flow cytometry, will be helpful in differentiating Polycythemia vera (PV) from secondarypolycythemia (1). Patients with chronic polycythemia who are negative for JAK2 V617F or exon 12 mutation and who lack the typical bone marrow findings of polycythemia vera will remain a diagnostic enigma. We collected 7 cases of patients who had persistent chronic erythrocytosis ranging from 1-15 years with negative driver mutations, lacking the typical PV bone marrow findings and absence of secondary causes such as smoking or malignancies. Blood mononuclear cells (MNC ) were collected as well as blood DNA extracted for 237 genes including EPO-R, PHD2, VHL or HIF-1-alpha (Familial erythrocytosis genes)with Next generation sequence, performed by Genoptyx lab (Carisbad, CA) and assayed for IGF-1R by flow cytometry as described previously (1). The results are shown in Table 1. Conclusion. All these 7 patients with elevated IGF-1R who had no evidence of familial erythrocytosis gene mutation nor had any secondary cause for erythrocytosis, likely carried the diagnosis of PV. It was shown that EEC formation in PV is due to IGF-1 hypersensitivity (2), andsecondary polycythemia do not show significantly elevated IGF -1R (1). Hence the elevated IGF-1R in these 7 patients strongly suggests the diagnosis of PV, re-affirming our proposal that simple procedures to assay blood MNC cells for IGF-1R by flow cytometry will be helpful in the diagnosis of PV and to be added as one of the minor criteria in the diagnosis of PV.