Matrix metalloproteinases and vascular endothelial growth factor expression in canine leukaemias

Matrix metalloproteinases (MMPs) and vascular endothelial growth factor (VEGF) play a coordinated role during neoplastic invasion and proliferation. VEGF and MMPs expression was investigated in canine leukaemias by immunocytochemistry (MMP-9, MMP-2, VEGF-A) and quantitative RT-PCR (MMP-2, MMP-9, MT1-MMP, TIMP-1, TIMP-2, RECK, VEGF-A, VEGF-164). Blood samples were obtained from dogs with acute leukaemia (AL; n= 11) and chronic lymphocytic leukaemia (CLL; n= 12). Levels of MMP-9, TIMP-1 and VEGF-A were higher in CLL than AL and controls. Expression of TIMP-2 and MT1-MMP mRNA was significantly higher in AL than CLL. Significant positive correlations were found between MMP-9 and TIMP-1 and between MMP-9 and VEGF-A in CLL. These results suggest a potential role of MMP-9, MT1-MMP, TIMP-1, TIMP-2 and VEGF in tissue migration and angiogenesis in canine leukaemia.