Cancer Chemoprevention

INTRODUCTION
Cancer is one of the deadly diseases, accounts for more than 12% of death globally. It is a silent disease characterized by unscheduled and uncontrolled proliferation of a cell with the potential to spread to other organs. Considering the progress and the past experience in dealing with health problems, prevention appears to be a practical, cost effective and achievable approach for the management of cancer. Cancer chemoprevention, a ‘prescription’ approach refers to slowing, blocking, or reversing the development of the disease by the administration of naturally occurring or synthetic compounds and based on the multi-step nature of carcinogenesis.

CARCINIGENESIS AND CHEMOPREVTION
          Carcinogenesis is a complex, multi-step and multi-factorial process characterized by at least three stages viz. initiation where cells acquire mutations via environmental mutagens, viruses etc. followed by promotion /progression where the initiated/mutant cells clonally expand and further transform to give rise to neoplasia. Compounds that inhibit any stage of carcinogenesis and delay or prevent cancer are called as chemopreventive   agents. Based on their mode of action, chemopreventive agents can be classified into two groups: blocking agents, which impede the initiation stage either by inhibiting the formation of carcinogen or preventing the carcinogens from reaching/reacting with macromolecule; and suppressing agents, which arrest or reverse the promotion and progression of cancer, mainly by affecting or perturbing crucial factors that control cell proliferation, differentiation, senescence or apoptosis. Numbers of natural and synthetic compounds have been shown to possess chemopreventive properties and many dietary constituents, in a variety of foods and beverages consumed by humans are receiving increasing attention. These agents have been shown to posses anti-initiation, and / or anti-promotion, and / or anti-progression activities in different in vivo...