Clinicopathologic correlations of bone marrow angiogenesis in chronic myeloid leukemia: a morphometric study

Various morphometric characteristics of microvessels, highlighted by means of anti-CD34 immunohistochemical staining, were evaluated in the bone marrow of 52 patients with chronic myeloid leukemia (CML) in chronic phase, in relation to several clinicopathologic parameters. Twenty control bone marrows and 15 cases of CML in blastic phase were also studied. Microvessel density (MVD), total vascular area (TVA) and several size- and shape-related parameters were quantitated in the region of most intense vascularization using image analysis. Overall, the group of chronic phase CML had higher MVD and size-related parameters and more branching microvessels than controls. Blastic phase was characterized by increased numbers of microvessels with a rounder shape and smaller caliber than chronic phase. A positive correlation emerged between marrow fibrosis and MVD as well as between white blood cell counts and rounder vessel sections. No relationship existed between microvascular parameters and Hasford or Sokal prognostic scores. In univariate analysis, overall and progression-free survival were adversely affected by MVD, size-related parameters, increased platelet count, age and spleen size. Multivariate analysis indicated that microvessel area was related to progression-free survival, whereas both MVD and area were significant prognosticators of overall survival, even when Hasford or Sokal scores are introduced into the model. Our data suggest that changes in angiogenic parameters may participate in the conversion of normal marrow to CML and ultimately to blastic transformation. More importantly, MVD and microvessel caliber are significant predictors of patient survival and progression.