Initiation, Promotion, and Progression

Carcinogenesis develops in three stages initiation, promotion, and progression. Chem-ical substances can act at the initiation stage or at the promotion stage. Moreover, some chemicals have both initiating and promoting activities. 

Figure 9.5 Karyotypic changes during initiation, promotion, and progression stages of carcinogenesis.

It has been established that the pathological processes of multistep carcinogenesis comprises initiation, promotion, and progression. The natural history of carcinogenesis and cancer provides a strong rationale for a preventive approach to the control of this disease and leads one to consider the possibility of active pharmacological intervention to arrest or reverse the process of carcinogenesis before invasion and metastasis occur. Such intervention is called chemoprevention. Tss... 

Studies in animal models have demonstrated that tea polyphenols can inhibit carcinogenesis at all stages, including initiation, promotion, and progression. This multifaceted inhibition of carcinogenesis process is attributed to a combination of antioxidative, antiproliferative, and proapoptotic effects of these polyphenols. Tea polyphenols have also been shown to inhibit the processes of angiogenesis, tumor metastasis, and invasion in animal models. ... 

---