CREB3L1 overexpression as a potential diagnostic marker of Philadelphia chromosome–negative myeloproliferative neoplasms

Discrimination of Philadelphia‐negative myeloproliferative neoplasms (Ph‐MPNs) from reactive hypercytosis and myelofibrosis requires a constellation of testing including driver mutation analysis and bone marrow biopsies. We searched for a biomarker that can more easily distinguish Ph‐MPNs from reactive hypercytosis and myelofibrosis by using RNA‐seq analysis utilizing platelet‐rich plasma (PRP)‐derived RNAs from patients with essential thrombocythemia (ET) and reactive thrombocytosis, and CREB3L1 was found to have an extremely high impact in discriminating the two disorders. To validate and further explore the result, expression levels of CREB3L1 in PRP were quantified by reverse‐transcription quantitative PCR and compared among patients with ET, other Ph‐MPNs, chronic myeloid leukemia (CML), and reactive hypercytosis and myelofibrosis. A CREB3L1 expression cutoff value determined based on PRP of 18 healthy volunteers accurately discriminated 150 driver mutation–positive Ph‐MPNs from other entities (71 reactive hypercytosis and myelofibrosis, 6 CML, and 18 healthy volunteers) and showed both sensitivity and specificity of 1.0000. Importantly, CREB3L1 expression levels were significantly higher in ET compared with reactive thrombocytosis (P