The Incidence of a Carcinogenic Factor in the Livers of Cancer, Noncancer, Cirrhotic, and Negro Patients*t

This is a report of a survey on the incidence of carcinogenic activity in extracts of various kinds of human livers. It is based on extracts from 67 cases tested in 896 mice. Carcinogenic activity in extracts of human liver has now been reported by Schabad (11); Kleinenberg, Neufach, and Schabad (7, 8); des Ligneris (4); Hieger (6); Steiner (13, 15); and Sanni~, Truhaut, and Gu&in (10); and has failed of confirmation only by Gummel (5). Despite all these papers it is not known at the present time what percentage of human livers contains this carcinogen, or with what types of tumors it is associated, although a few data are available on the latter point. For example, Schabad found that the extract of a liver from a patient with carcinoma of the stomach was carcinogenic, and Hieger stated that some of his tumors were induced by extracts of livers from persons who had lymphosarcoma. The other papers mentioned above gave the results either on extracts obtained from pooled livers, on extracts pooled before testing, or on animals injected with extracts from more than one liver. Des Ligneris and Steiner both reported that extracts of livers from persons who had no neoplasm also produced tumors at the site of injection. The former tested Bantus in South Africa, and the latter white persons in America. Again, the carcinogenic activity cannot be correlated with the major disease diagnosis because the livers were pooled for extraction, and for the same reason it is impossible to know what percentage of the livers contained the carcinogen. In order to establish the r61e, if any, of this liver carcinogen in the causation of human cancer it is important to know whether it is present in every