The Production of Benign and Malignant Skin Tumours in Mice Painted with Bantu Liver Extracts

Abstract

One of the most striking differences in cancer localization between Europeans and several native races living in tropical and semi-tropical regions of Asia and Africa concerns the occurrence of primary liver cancer. While this form of cancer is known to be of rare occurrence among Europeans, including those living in Asia or Africa, it is, both in the Dutch East Indies and in Southern Africa, the most frequent form of cancer in native males (much less so in native females). The native races concerned are the Malays and the Bantu. The reason for the frequent occurrence of liver cancer in these races is not yet known. Some authors, remembering the inherited tendency of certain strains of mice to develop cancer in particular organs, have suggested the possibility that the localization of cancer in the liver is a racial peculiarity. Others think that there is nothing “racial” in this localization and that external circumstances, as exposure to such endemic diseases as schistosomiasis, malaria, and various worm infections, or the absence of vitamin A in the diet, are the responsible factors. Certain alcoholic drinks have also been suspected. The fact, shown by Berman, that, among the Bantu workers in the Witwatersrand gold mines, liver cancer occurs in a much greater proportion in those originating from Portuguese East Africa (Mozambique) than in those from the Union of South Africa—though all are of the same race—would point to an external cause. There is more malaria, more schistosomiasis, possibly also more vitamin-A deficiency and a larger consumption of alcoholic drinks in the Portuguese colony. It has been established by Gillman (personal communication) that in the South African Bantu the proportion of binucleated liver cells is five or six times greater than in Europeans. Is this to be interpreted as a manifestation of hyperplasia? Strachan, who has a very large experience of Bantu pathology, states (personal communication) that a normal Bantu liver is very seldom encountered; in most instances there is, to a varying extent, periportal small-cell infiltration, which is frequently the prelude to cirrhosis; there is usually, also, increased pigment formation, such as haemochromatosis. These facts suggest the existence of a connection between certain metabolic disturbances, possibly of a toxic origin, and the occurrence of malignant change in the Bantu liver. These disturbances are not necessarily specific for the Bantu; but they are certainly much more frequent and more pronounced than in the average European. Their nature, for the present, remains a mystery.