Circulating Cytokine Levels as Markers of Inflammation in Philadelphia Negative Myeloproliferative Neoplasms: Diagnostic and Prognostic Interest

Figure 2

Role of THBS secreted by PMF megakaryocytes in angiogenesis and myelofibrosis development. Megakaryocytic THBS can lead to fibrosis via activation of TGFβ1 signaling and TIMPs but simultaneously inhibits angiogenesis via its receptor CD36 and inhibition of VEGF signaling. Nevertheless, myelofibrosis is associated with increased vascularization which could be mediated by PDGF signaling. The immunohistochemical image shows strong THBS expression in clustered PMF megakaryocytes and in small proplatelet depositions in situ.