Studies were performed to test the applicability of the molecular correlation concept developed in chemically induced transplantable rat hepatomas to virally induced transplantable hepatoma in chicken. In a comparison of the activities of carbohydrate, purine, and pyrimidine key enzymes in rat and chicken hepatomas, similar patterns were observed in rodent and avian tumors. These results show that the enzymatic imbalance elucidated in chemically induced rat hepatomas is applicable to the virus-induced hepatoma in chicken, independent of the nature of the carcinogenic agent and the species.