Increased Dkk-1 plasma levels may discriminate disease subtypes in myeloproliferative neoplasms.

Alterations in the bone marrow niche induced by abnormal production of cytokines and other soluble factors have been associated with disease progression in classical BCR-ABL1 negative myeloproliferative neoplasms (MPN). Variations in circulating proteins might reflect local disease processes and plasma proteome profiling could serve to identify possible diagnostic and prognostic biomarkers. We employed a human cytokine array to screen for 105 distinct analytes in pooled plasma samples obtained from untreated young MPN patients (<35 years) with different clinical phenotypes and driver mutations, as well as from healthy individuals. Among molecules that exhibited significantly increased levels in MPN patients versus controls, the top of the list was represented by Dickkopf-related protein 1 (Dkk-1), which also showed the highest potential for discrimination between MPN subtypes. In the next step, a quantitative ELISA was used to measure plasma Dkk-1 levels in 30 young-onset MPN-10 essential thrombocythemia (ET), 10 polycythemia vera (PV), 10 pre-fibrotic primary myelofibrosis (pre-PMF)-and 10 controls. The results suggested that plasma Dkk-1 levels could differentiate ET from pre-PMF, in JAK2 V617F-positive as well as in CALR-positive patients, and also ET from PV in JAK2 V617F-positive patients.