Increased MVD at the prefibrotic stage of PMF suggested angiogenesis as an early event signalling the development of fibrosis, according to Boveriet al. The study found that the grade of fibrosis increased with increasing MVD.6 Lekovicet al. found that CD34-MVD and CD105-MVD strongly (p = 0.001 and p = 0.001, respectively) linked with the grade of bone marrow fibrosis in the entire cohort of MPN patients.19 These observations were in line with the findings of the current study. This evidence concerns the gene ENG and primary myelofibrosis.