The Generation of Cancer: Initiation,promotion,progression and the multiple influences of the environment

Carcinogenesis is a multi-stage process, conventionally divided into initiation, promotion and progression. Most carcinogens are initiators, but promoters may be equally important environmental factors in the development of cancers. The environment can also influence the pathways by which carcinogens are activated and targeted onto particular tissues and the mechanisms by which carcinogenic injury is corrected or eliminated.

Despite recent studies on the mechanisms of promotion, progression is imperfectly understood, but agents (possibly including promoters) acting at this stage might influence the rate of emergence of clinical malignancy from pre-malignancy.