In turn, the expression of VEGFR2 correlated with the grade of myelofibrosis (p = 0.001; ρ = 0.53, 95% CI 0.25-0.71) and the presence of nestin-positive stem cell niches (p = 0.001; ρ = 0.53, 95% CI 0.22-0.74). This evidence concerns the gene KDR and myelofibrosis.