Clinical aspects of alpha 1-fetoprotein determination in human liver cancer and in humans and experimental animals at carcinogenic risk.

Recent findings concerning the significance of alpha 1-fetoprotein (AFP) as a tool for clinical diagnosis and monitoring of tumor diseases are reviewed briefly. The applicability of this protein marker to the early diagnosis of patients at carcinogenic risk is discussed. In addition, experimental data obtained with a model of chemical hepatocarcinogenesis are reported. The increase of proliferative activity in precancerous liver tissue preceded AFP production under experimental conditions with azodyes and aflatoxin B1 as carcinogens. Immunohistochemical analysis of the relation of AFP to changes of cell populations and to liver tissue rearrangement led to the conclusion that AFP-producing cells cannot be precursors of malignant hepatocytes; however, AFP appeared to be linked to dividing hepatocytes at a certain step of cell differentiation regardless of the stages of precancerous development. A decrease in the rate of nuclear RNA synthesis was observed in both precancerous and tumor tissues. A possible analogy between the early phase of AFP production in animal carcinogenesis and that in human carcinogenesis is considered.