Introduction
Diffuse large B cell Lymphoma (DLBCL) is the most common subtype of Non-Hodgkin Lymphoma (NHL). DLBCLs constitute 30-40% of NHL and more than 80% of aggressive lymphomas(1). Among the treatment targets of lymphomas is angiogenesis, which is increasingly important and is the main subject of many cancer treatment researches. Angiogenesis is regulated by the balance between angiogenic and anti-angiogenic factors. Microvascular density and tumor angiogenesis were found to be poor prognostic factors in patients with DLBCL receiving anthracycline-based chemotherapy(2). VEGF (Vascular endothelial growth factor), PDGF (Platelet derivated growth factor) are the leading angiogenic factors, and thrombospondin-1 is the leading antiangiogenic factor. In studies conducted with serum VEGF levels of patients with a diagnosis of DLBCL, those with high serum VEGF levels were found to be associated with poor prognosis(3). In mice models with DLBCL, apoptosis in pericytes, one of the important elements of angiogenesis, and a decrease in tumor volume were observed with imatinib treatment targeting PDGFR-β(4). It was observed that high level of thrombospondin expression in many tumor cell lines inhibits tumor cell angiogenesis and progression(5, 6). Our aim in this study is to immunohistochemically investigate the relationship between the staining rates of mainly antiangiogenic factor thrombospondin-1, VEGF and PDGFR-in tissue preparations in patients diagnosed with DLBCL as a result of lymphadenopathy biopsy and their clinical features at the time of diagnosis, response to treatment and prognosis.