PATHOLOGICAL COMPARISON BETWEEN SPONTANEOUSLY DEVELOPED AND CHEMICALLY-INDUCED LIVER CANCERS IN LEC RATS WITH HEREDITARY HEPATITIS

To investigate the pathological differences between spontaneously deve loped 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'-meth yl-4-dimethylaminoazobenzene (3'-Me-DAB) for 12 weeks, and then fed ba sal 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 tha n non-treated rats. The chemically-induced cancers were strongly relat ed to Edmondson classification. Metastasis and transplantability of th e chemically-induced cancers were higher than spontaneous cancers. LEC rats are highly susceptible to the chemical carcinogen with the initi ated status of hepatocarcinogenesis.