Human liver cancer is increasing worldwide, including in Hungary. The detec
tion of liver tumors in premalignant or early malignant states is essential
for successful treatment. MC-29 virus-induced chicken hepatoma and rodent,
fish and monkey models for chemical hepatocarcinogenesis were studied and
compared to humans. Changes in phenotypic enzyme alterations and in the exp
ression of certain oncogens and growth factors characterize the experimenta
lly induced hepatomas, and might also be characteristic of human premaligna
nt and malignant focal liver lesions. Fish hepatocarcinogenesis is useful f
or studying compounds in environmental pollution. Increased expression of t
ransforming growth factor a can be observed both in experimental and human
liver tumors. Increased tumor incidence was detected in transgene mice cont
aining both transforming growth factor alpha and c-myc genes. Animal models
of hepatocarcinogenesis help to understand the development of liver tumors
. Methods applied in studies using those models are useful in the study of
premalignant and malignant human liver lesions.