The two-stage clonal expansion model as an example of a biologically based model of radiation-induced cancer.

A model with two stages and clonal expansion (TSCE) is reviewed as a prototype for biologically based models of cancer development. Applications of the TSCE model to data sets for animals and humans for particle radiation (alpha particles) are presented. The results suggest that the radiation not only influences the initiating mutation, but may also act as a promoter. A possible mechanism for the promoting action is described. The consequences of these results for the shapes of the radiation dose-response curves at low doses and dose rates are discussed.