Increased bone marrow microvascular density in haematological malignancies is associated with differential regulation of angiogenic factors.

Antiangiogenic drugs are currently tested in haematological malignancies. As these drugs target different angiogenic regulators, and as cancers are inherently heterogeneous, a detailed characterization of angiogenesis in individual cancers is needed. Hence, we measured bone marrow microvessel density (MVD), plasma concentrations of eight angiogenesis-related parameters and the expression in blood mononuclear cells of 40 angiogenesis-related mRNAs in 93 patients with haematological neoplasias (acute myeloid leukaemia; chronic lymphatic leukaemia; multiple myeloma (MM); or non-Hodgkin's lymphoma (NHL)) before start and after completion of cancer therapy. Compared with healthy individuals, the patients had significantly increased bone marrow MVD, especially patients with advanced stage disease. A novel finding was that patients with NHL also had increased bone marrow MVD. The plasma levels of vascular endothelial growth factor (VEGF), interleukin (IL)-6 and IL-8 were significantly increased. VEGF levels were highest in those who did not achieve complete remission after cancer therapy. The mRNA expression of IL-8 was upregulated 15-fold. Our data show that patients with haematological malignancies have increased bone marrow MVD; hence, supporting the notion that bone marrow angiogenesis plays a role in the pathogenesis and progression of these cancers. VEGF, IL-6 and IL-8 seem to contribute to the malignant phenotype.