O6-alkylguanine-DNA-alkyltransferase activity in relation to the promutagenic methylation damage in bladder DNA from humans predisposed to bladder cancer associated with schistosomiasis : Badawi1,3, A.F., Cooper1, D.P., Mostafa3, M.H., Aboul-Azm2, T., Margison1, G.P. and O'Connor1, P.J. 1CRC Section of Carcinogenesis, Paterson Institute for Cancer Research, Manchester M20 9BX, UK, 2Medical Research Institute, 3Institute of Graduate Studies & Research, University of Alexandria, Egypt