ABSTRACT
Cancer is the end-stage manifestation of heterogeneous and chronic disease processes. Over the last several decades, a search for a cancer cure has largely been focused on developing chemotherapeutic agents, radiotherapy, and surgical intervention. Nonetheless, the incidence and mortality of cancer, in general, are still increasing. The number of cancer-related deaths is expected to double in the next 50 years despite current advances in cancer prevention and treatment [1]. In fact, the aforementioned conventional strategies, largely implemented after the diagnosis of cancer at the advanced stage, have been proven unsatisfactory to cure cancer. This is because the malignant lesions exhibit heterogeneity in terms of genotypic and phenotypic characteristics, which makes it impractical to nd a speci c molecular target for the de ned cure for cancer. Moreover, many of the clinically approved cytotoxic drugs exert deleterious effects on the normal tissues, thereby devastating the quality of life [2]. In this context, chemoprevention has recently attracted much attention as an alternative strategy for the management of cancer. Chemoprevention, the term coined by Michael B. Sporn, refers to the use of nontoxic chemical substances of natural or synthetic origin to inhibit, retard, or even reverse the speci c stage of carcinogenesis [3]. A wide spectrum of preclinical and clinical studies put a strong scienti c basis on the success of the chemoprevention strategy in reducing the global burden of cancer. Based on the advances in chemoprevention research in the past three decades, there is now a paradigm shift from cancer treatment toward cancer chemoprevention [2,4,5].
