Intravascular large B-cell lymphoma: the heterogeneous clinical manifestations of its classical and hemophagocytosis-related forms.

these cells may predict response to chemotherapy. 21 While this observation is intriguing, simpler and more reproducible predictive markers have been used. However, this observation may be further explored in selecting patients for anti-angiogenesis clinical trials. While it has been years since anti-angiogenic therapy has been introduced for the treatment of cancer, such therapy remains only marginally effective and is associated with significant potential toxicity. Characterization of tumor-associated EPC may provide clues for more specific anti-angiogenesis therapy that may selectively target tumor vasculature, thus minimizing toxicity to normal vessels. The study by Igreja and colleagues is another step in the right direction. marrow origin of endothelial progenitor cells responsible for postnatal vasculogenesis in physiological and pathological neovascularization. Transplantation of ex vivo expanded endothelial progenitor cells for therapeutic neovasculariza-tion. and haematopoietic stem cells: novel targets for anti-angio-genesis therapy? Nat Rev Cancer 2002;2:826-35. al. Impaired recruitment of bone-marrow-derived endothe-lial and hematopoietic precursor cells blocks tumor angio-genesis and growth. et al. Transplanted adult hematopoietic stems cells differentiate into functional endothelial cells. Cook BP, et al. Endothelial precursor cells as a model of tumor endothelium: characterization and comparison with mature endothelial cells. of autologous endothelial progenitor cells for therapeutic neovascularization of myocardial ischemia. progenitor cell trafficking in patients with myeloprolifera-tive diseases. Zeoli A, Pegoraro M, et al. c-Kit by interacting with the membrane-bound ligand recruits endothelial progenitor cells to inflamed endothelium. Blood 2007;[Epub ahead of print]. al. Identification and clinical significance of circulating endothelial progenitor cells in human non-small cell lung cancer. Shaked Y, et al. Maximum tolerable dose and low-dose metronomic chemotherapy have opposite effects on the mobilization and viability of circulating endothelial progenitor cells. I n this issue, Ferreri and the International Extranodal Lymphoma Study Group document that the clinical features of patients with intravascular lymphoma (IVL) vary based on the presence or absence of hemo-phagocytosis (HPC), rather than geographical region, differentiating IVL into classical and HPC-related forms. IVL is defined morphologically by the distribution of tumor cells exclusively in the lumina of blood vessels. IVL has unique clinical characteristics due to massive involvement of extranodal sites, without lym-phadenopathy or leukemic manifestations, and is currently regarded as a rare entity listed in the category of diffuse large B-cell lymphomas of the World Health Organization (WHO) classification.