“…Increased risks of colorectal adenoma and adenocarcinoma, and of stomach, breast, lung and PCs have been weakly or clearly associated with potential or estimated HA exposure in most ( Shiffman and Felton, 1990;Gerhardsson de Verdier et al, 1991;Lang et al, 1994;Probst -Hensch et al, 1997;Ward et al, 1997;Kampman et al, 1999;Norrish et al, 1999;Sinha et al, 1998aSinha et al, , 1999Zheng et al, 1998Zheng et al, , 1999, but not all (Lyon and Mahoney, 1988;Muscat and Wynder, 1994;Augustsson et al, 1999 ), case ± control studies investigating possible associations between increased human cancer risk and dietary HA -exposure categories based on self -reported meat -cooking methods and meat -doneness preferences. Positive studies have tended to be those in which interactions among meat types, intake frequencies, cooking methods and /or cooking doneness preferences were reflected in the categories used to classify relative HA -exposure levels (Probst -Hensch et al, 1997;Ward et al, 1997;Sinha et al, 1998bSinha et al, , 1999Zheng et al, 1998 ).…”