Cancer prevention: recent progress and future opportunities.

Knowledge gathered during the past few decades from the fields of cancer epidemiology, carcinogenesis, biochemistry, and molecular biology, much of which was communicated through the pages of the journal Cancer Research, provides powerful new strategies for cancer prevention. Indeed, I believe that it is possible to draft a blueprint for a comprehensive approach to cancer prevention, to be used as we approach the 21st century. This plan includes: (a) expanded epidemiological and laboratory studies to identify the specific causes of human cancers; (b) intervention studies, such as risk reduction by the cessation of cigarette smoking, dietary modifications, chemoprevention, and the development of vaccines for viral agents implicated in human cancer (i.e., hepatitis B, human papilloma virus, Epstein-Barr virus, and certain retroviruses), and (c) early detection and screening. Concepts and methods that have developed in the field of cellular and molecular biology will accelerate this progress. Indeed, we are currently in a very exciting phase of cancer research that brings together fields of cancer research which in the past were often disparate and disconnected, i.e., basic laboratory studies, epidemiology, prevention, and treatment. Thus, the astounding advances in our understanding of the molecular biology of cancer provide a unified concept of the nature of the cancer cell and also suggest new clinical approaches to cancer etiology, prevention, and treatment. Many of the biomarkers being developed for etiological studies, using the approach of molecular epidemiology, can also serve as biomarkers or intermediate end points to evaluate the efficacy of dietary intervention and chemoprevention studies. Some of these biomarkers will also be useful for evaluating the efficacy of cancer therapy. Furthermore, certain compounds being developed for cancer chemoprevention, e.g., the retinoids, may also be useful in the therapy of fully established neoplasms. It seems likely, therefore, that even before the year 2000 these powerful and unifying themes will accelerate advances in both cancer prevention and treatment, thus leading to major reductions in both the incidence and mortality of human cancer.