Current paradigms of cancer chemoprevention

Abstract

Cancer chemoprevention has been continually evolving ever since the term was coined in the 70s. From the original approaches of identifying chemopreventive agents from the dietary constituents based on the epidemiological data to the current status of adapting them from the molecular targets, significant understanding of cancer as a disease and its possible prevention has been achieved. The identification of the chemopreventive agent from a complex mixture of natural product extracts involves numerous steps including bioassay guided fractionation; evaluation of the extracts, fractions and isolated new chemicals selectively using in vitro and in vivo experimental models; and understanding the mechanism of their action. This in turn provides identification of the molecular target for the parent drug and a basis for the synthesis of more effective, nontoxic analogs. A chemopreventive agent by definition needs to be nontoxic, since it is expected to be consumed by healthy people that may be at a higher risk of developing cancer. This makes a case for these agents to be evaluated as possible adjuvant chemotherapeutic agents. It is expected that more selective delivery methods to the target organs to eliminate toxicity and use of chemopreventive agents as adjuvant chemotherapeutic agent using personalized approaches will be the next steps for chemoprevention.