ABSTRACT
Cancer occurs as the outcome of a carcinogenesis process that involves three distinguishable but closely connected stages: (a) initiation stage, which is the outcome of a rather rapid and irreversible outcome of assault on a normal cell, leading to a transformed or initiated cell, (b) promotion phase, in which the initiated cell changes to a preneoplastic cell, and (c) the progression stage during which the preneoplastic cell becomes a neoplastic cell. Cancer therefore arises from one single cell. The crucial initiation phase may be due to the initial uptake of a carcinogen and the subsequent stable genotoxic damage caused by its metabolic activation. Other causes of cancer initiation include oxidative stress, chronic inammation, and hormonal imbalance.3 The WHO has identied these changes as the result of the interaction between a person’s genetic factors and three categories of external agents, including
• Physical carcinogens, such as ultraviolet and ionizing radiation • Chemical carcinogens, such as asbestos, components of tobacco smoke, aatoxin
(a food contaminant), and arsenic (a drinking water contaminant) • Biological carcinogens, such as infections from certain viruses, bacteria, or
parasites
Perhaps beyond the initiation, promotion, and progression stages of cancer is the metastasis phase during which the cancerous cells invade other otherwise healthy cells, tissues, and organs with the help of adhesion molecules and angiogenic factors. Cancers
can therefore be considered as attempts by cells to adapt to a changing environment. Countries undergoing nutritional transition from traditional high-vegetable, low-fat diets to processed high-fat, high-animal protein, and chemical-laden Western diets may be more vulnerable to noncommunicable diseases, including cancers. The introduction of novel food chemicals, preservatives, and additives will exert additional stress in the normal functioning of the cells. It has been suggested that the growth of powerful economic institutions and globalization is accelerating, mixing many cancer risk factors, and generating new cancer risk factors.4 Dr. Annie Sasco of Bourdeux University, France argues that concurrent with globalization are apparent risk factors such as modern diet, addictive products, pharmaceuticals, and toxic and waste products, which must be factored into cancer prevention and treatment programs.4
