Immunohistochemical expression of angiogenic cytokines in childhood Hodgkin lymphoma

This immunohistochemical study was carried out to evaluate the role of vascular endothelial growth factor (VEGF), matrix metalloproteinase-2 and -9 (MMP-2 and MMP-9), their inhibitor (tissue inhibitor of metalloproteinase-1, TIMP-1), and microvessel density (MVD) in the clinicopathologic behavior of childhood Hodgkin's lymphoma (HL).Paraffin-embedded histologic sections from 15 children with HL were immunohistochemically stained with MMP-2, MMP-9, TIMP-1, VEGF, and CD31 antibodies to investigate the correlation between the expression of these markers and the clinicopathologic characteristics of HL.Expression of MMP-2 and VEGF in Hodgkin and Reed–Sternberg cells (HRS) was more frequent in nodular sclerosis than in other subtypes (p=0.07 and 0.08, respectively). None of the study parameters in HRS cell were associated with age, sex, disease stage, extranodal disease, and the occurrence of bulky tumor. There was a trend toward advanced stage in negative TIMP-1 staining in HRS cells (p=0.06). In reactive lymphocytes, MMP-2 expression was correlated with MVD (r=0.68, p=0.005), and MMP-9 expression was correlated with B symptoms (p=0.003). Also, low TIMP-1 expression in reactive lymphocytes was frequently found in patients with advanced stage (p=0.048). There was a positive correlation with the ratio of MMP-2 expression in reactive lymphocytes and MVD (r=0.68, p=0.005). Expression of MMP-9 in reactive lymphocytes was correlated with MVD without statistical significance (r=0.487, p=0.06).Our results suggest that, as in many solid tumors, angiogenesis and angiogenic factors may play an important role in childhood HL. Larger series of patients are needed to determine the prognostic value of angiogenesis in childhood HL.