ABSTRACT
One of the most important public health and medical practices of the new century is the prevention of cancer. Much progress has been made in this new field, but much work remains before widespread use becomes practice. Cancer chemoprevention is defined as the inhibition, reversal, and retardation of the cancer process. The cancer process, called carcinogenesis, requires two to four decades to reach the end point called malignant cancer. The process follows multiple, diverse, and complex pathways in a stochastic process of clonal evolution. Many have shown that these pathways are responsive to inhibition, reversal, or retardation at various points. Much basic research is devoted to identifying the many genetic lesions and epigenetic processes associated with the progression of cancer. Normal regulatory genes are mutated, making them insensitive to normal regulatory signals. Tumor suppressor genes are deleted or mutated, rendering them inactive. Thus there is a wide range of defects in cellular machinery that can lead to evolution of the cancer phenotype. To conquer this diverse disease, we must attack multiple key pathways at once for a predetermined period of time.
