CCL2 and acquired polycythemia vera: Ultimately, we evaluated the diagnostic/prognostic significance of CCL2 gene expression level; ROC analysis showed that the best cut-off values of CCL2 gene expression level that discriminates MF patients (PMF and Post-PV/ET-MF) from other subjects and from PV + ET patients were >1.36 and >1.52 yielding a sensitivity of 82.61% and 80.43% and a specificity of 78.48% and 73.17% with an AUC of 0.932 and 0.919 (p < 0.001), respectively (Figure 2 and Figure 3).