Inequalities in health reflect social inequalities in society. The incapacity of our society to eliminate poverty is indeed one of the most blatant examples of failure in prevention. Every individual's health history is characterized by life-long influences and superimposed short-term factors, but health biographies of the rich and the poor show divergences that are the result of the accumulation and interaction of a series of events that may be quantitatively and qualitatively different. Schematically this could, for example, mean that certain individuals, or certain segments of the populations, are exposed more frequently and to more hazardous agents than others and/or less frequently to protective agents. Sanitary conditions are worse, mortality higher, survival rates of cancer patients lower, and life expectancy shorter in developing countries than in industrialized countries. The projection of the total number of cancer cases in the next decades indicates a general increase, proportionally greater in developing than in industrialized countries. Semin Oncol 28:207-209.