Angiogenesis in bladder tumours: prognostic indicator and therapeutic target.

Angiogenesis is a complex, multi-step process which leads to the formation of new blood capillaries (neovessels) from preexisting vessels. It is essen tial top the growth of solid tumours and tumour metastasis (tumour angiogen esis). This process is initiated by the synthesis, by tumour cells and non- malignant tumour-associated cells, of growth factors called antigenic facto rs or inducers. bFGF (basic Fibroblast Growth Factor) and VEGF (Vascular En dothelial Growth Factor) are the two angiogenic factors involved in bladder tumour angiogenesis. The angiogenic activity of a bladder tumour can be measured by the microvas cular density (MVD), considered by, some authors to be an independent progn ostic indicator of recurrence and survival in the group of invasive bladder tumours. VEGF expression in bladder tumours and biological fluids (serum, urine) appears to be a predictive marker of the risk of progression of supe rficial bladder tumours. Urinary bFGF assay reveals high levels in patients with bladder tumour, but this elevation is not specific to bladder tumours . Inhibition of tumour angiogenesis has become a therapeutic target. Intraves ical suramine and a fumagillin analogue (TNP-470) have given promising resu lts in terms of efficacy and safety in the treatment of bladder tumours.