[Ratio of spontaneous and o-aminoazotoluene-induced hepatocarcinogenesis in mice].

No correlation was found between the frequency of spontaneous and o-aminoazotoluene (o-AAT)-induced hepatic tumours in mice. High susceptibility to tumour induction with o-AAT in mice both genetically susceptible (strains CBA and A/He) and resistant (strains DBA/2J and DD) to spontaneous hepatocarcinogenesis was detected. The CC57BR mice predisposed to spontaneous hepatomas were insensitive to their induction with o-AAT. The model described may be helpful in studies of the nature of the initiation and promotion stages of hepatocarcinogenesis.