Pathological comparison between spontaneously developed and chemically induced liver cancers in LEC rats with hereditary hepatitis

To investigate the pathological differences between spontaneously developed and chemically induced liver cancers in LEC rats with hereditary hepatitis, eight-week-old LEC rats were fed 0.06% or 0.03% of 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) for 12 weeks, and then fed basal diet. Spontaneous liver cancers occurred in 60.4% of the LEC rats, while 3'-Me-DAB induced cancers in all LEC rats. The survival periods of chemically (0.06%) treated LEC rats were significantly shorter than non-treated rats. The chemically-induced cancers were strongly related to Edmondson classification. Metastasis and transplantability of the chemically-induced cancers were higher than spontaneous cancers. LEC rats are highly susceptible to the chemical carcinogen with the initiated status of hepatocarcinogenesis.