The results here show that VEGF overexpression can alter the rate of human xenografted tumour growth in vivo and moreover that VEGF165b can antagonise the effects of VEGF165, thus confirming the role of the C terminus of VEGF in determining its function and the importance of the ratio of VEGFxxxb to VEGFxxx in the progression of tumour growth. This evidence concerns the gene VEGFA and neoplasm.