Molecular epidemiological studies conducted within different geographic regions or in different races and tumour stages/grades have revealed that up to 84% of bladder TCC carried activated H-Ras (Fontana et al, 1996; Hong et al, 1996; Vageli et al, 1996; Yu et al, 1996; Saito et al, 1997; Olderoy et al, 1998; Przybojewska et al, 2000). This evidence concerns the gene HRAS and neoplasm.