Autochthonous, acetoxymethylmethylnitrosamine-induced colorectal cancer in rats: a useful tool in selecting new active antineoplastic compounds?

Acetoxymethylmethylnitrosamine (AMMN)-induced autochthonous colorectal rat adenocarcinomas are an interesting model for the secondary evaluation of new antineoplastic compounds aimed at predicting clinical activity. These orthotopic tumors mimic the human situation closer than conventionally used transplanted systems with respect to their relatively slow growth, their genuine histology, their original tumor-host interaction and their low chemosensitivity to clinically used drugs. 4-Amino-N-(2' aminophenyl) benzamide, 4-Oxo-2-phenyl-4H-1-benzopyran-8-acetic acid, dichloro-bis(1-phenyl-1,3-butanedionato)titanium(IV) and diethoxy-bis(1-phenyl-1,3-butanedionato)titanium(IV) are four new agents, which have shown promising anticancer activity in this model, but which failed to show high activity in fast-growing transplanted systems. Clinical studies on these agents are highly warranted. A comparison of predicted and actual clinical anticancer activity will finally point to the appropriate means of drug selection.