MALIGNANT CELLULAR EVOLUTION: An Analysis of the Causation and Prevention of Cancer

Abstract

The appearance of a cancerous strain of cells within the multicellular organism is thought of as analogous to the appearance of a new variant or species of animal or plant. This evolutionary concept of cancer is considered compatible with the epidemiological and pathological distribution of malignant tumors. Variability is visualized as an inescapable concomitant of every cell division. The action of viruses may be different from other mutagens. They may endow certain cells with a large competitive advantage. Growth and repair of tissues provide an opportunity for evolution of cells. Replacement of cells with lesser proliferative vigor by cells with greater vigor is the essential basis of evolutionary neoplasia. For example the adult neuron does not reproduce; therefore it does not become involved in malignant neoplasia. It is only by selection from serial reproduction t hat minute individual differences can be added to produce large deviations of heritable characteristics. This principal has been used by animal and plant breeders. Although formation of the glandular endometrium necessitates much serial reproduction menstruation may be regarded as a physiological eraser of endometrial neoplasia. With the menopause more progressive serial reproduction is possible. The effect of chronic irritation is much greater if replacement of cells is localized. Effects of ionizing radiation and tobacco smoke agree with t he concept of malignant cell evolution. This concept of malignant cellular evolution suggests that it is an inescapable concomitant of all multicellular life. The value of avoiding unnecessary exposure to mutagens is stressed.