The relation between experimental liver carcinoma and liver cirrhosis induced by successive administration of p-dimethylaminoazobenzene and carbon tetrachloride.

p-Dimethvlaminoazobenzene (D.A.B.) was fed to rats for periods of 4 to 24 weeks. The treatment was followed by repeated injections of carbon tetra chloride (CCl4). The groups thus treated were compared with groups which were fed on basal diet after D.A.B. was discontinued . 1) CCl4 was found to act as a promoting factor and to accelerate the carcinogenic process of D.A.B. 2) In comparison with the groups which were fed on basal diet after D .A.B. was discontinued, the groups in which D.A.B. was followed by repeated administra tion of CCl4 showed significantly higher incidence rates of liver carcinoma , liver cirrhosis, liver carcinoma with liver cirrhosis, and nodular hyperplasia . It was further ascertained that this was especially remarkable in the groups given D.A .B. for 8, 10 or 12 weeks. 3) The administration of CCl4 did not influence the histological pattern of D.A.B.-induced liver carcinoma. 4) Positive correlation was found between the incidence of liver carcinoma with liver cirrhosis and nodular hyperplasia. The possibility was pointed out that liver carcinoma developed on the basis of liver cirrhosis and nodular hyper plasia. 5) The modification of hepatic changes in the course of D.A.B. carcinogenesis by the administration of CCl4 was described, and its effect on the development of liver carcinoma was discussed.