Some Aspects of the Epidemiology and Etiology of Esophageal Cancer With Particular Emphasis on the Transkei, South Africa

Some mechanisms operative in carcinogenesis a review

Multiple factors contribute to the development of neoplasia. Sometimes a single agency can bring about a tumour if it has many different effects, but at other times a tumour arises more insidiously due to a succession of events [240,241] which by themselves may be innocent. Alterations in the genome of the cell are at the fore-front of our interest because they can be brought about by most of the carcinogenic agents we know. The cell can repair some such alterations but both forward and destructive mutations do appear. The roles of cell proliferation, cell differentiation, the immune mechanism and carcinogen-activating enzymes are beginning to be understood. The effects of dose, route of administration, and of other agents given at the same time [242-245] must not be lost sight of. Other factors no doubt will be added as we begin to look at the structure and function of cell-surface membranes [246-248], at host susceptibility genetics [26, 249], and at the generation of carcinogens inside the body [250,251]. We are only beginning to understand carcinogenesis. In no single instance do we as yet know how a tumour comes about in full details of molecular biology. It is possible that fully rational treatment of cancer will not be possible until we have such an understanding. Once a tumour becomes independent of carcinogenic factors, it continues to develop in a bizarre fashion which makes its study and treatment by all means other than surgery difficult.

Cancer of asians in kenya

The frequency of various cancers among Indian immigrants in Kenya was compared to corresponding data among native Africans and Indians in the regions of India from which most of the studied population originally migrated. The Kenyan Indians do not have the cancer pattern of their home country nor do they have the cancer pattern of indigenous Africans. They have instead, like Europeans and North Americans, a higher risk of cancer of the lung, breast and the large intestine. It is suggested that this is related to enbironmental factors and variations in living habits.