[Present chemoprevention and future vision].

Cancer chemoprevention is defined as the use of natural or synthetic agents to reverse, suppress or prevent carcinogenic progression to invasive cancer. The success of several clinical trials within high-risk patients suggests that chemoprevention is a rational and promising strategy. This review will resume the principal molecular mechanisms of chemoprevention and discuss results and clinical outcome of selected clinical trials. The difficulties in clinical application and future directions will be highlighted.