Angiogenesis and mast cells in non-Hodgkin's lymphoma: A strong correlation in angioimmunoblastic T-cell lymphoma

Mast cells are likely to play a role in angiogenesis under pathological con ditions. Solid tumor growth is dependent on angiogenesis, but the influence of mast cells on angiogenesis in non-Hodgkin's lymphoma, (NHL) is not clea r. We investigated mast cell number and vessel count in 61 cases of NHL. We also evaluated expression of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), both important cytokines for angiog enesis. The number of mast cells was greater in T-cell lymphomas than in B- cell lymphomas. Of the T-cell lymphomas, the greatest number of mast cells was observed in the angioimmunoblastic T-cell lymphoma (AIL). In all NHLs, significant correlation was found between vessel count and the number of ma st cells (p < 0.0001) and between vessel count and the number of VEGF-expre ssing cells (p < 0.05) but not between vessel count and bFGF-expressing cel ls. Strong correlation was detected between the number of mast cells and th e number of VEGF-expressing cells (p < 0.0001) in all NHLs, Double fluoresc ence staining of VEGF mRNA and mast cell tryptase revealed that mast cells expressed VEGF mRNA. Our data suggest that mast cells play a very important role in angiogenesis by expressing VEGF in NHL, especially in AIL.