Proliferation models in tumours

Cell cycle models can be helpful in understanding the organization and kinetics of cellular proliferation. Until recently, models tended to fall into two classes, those assuming that cells normally reside in a quiescent state and are recruited into and through the cell cycle, and those that attempted to accommodate the heterogeneity seen in human tumours. The proliferation plane model combines these two approaches into a unified model encompassing recruitment and retardation in the cell cycle. It provides a framework to re-evaluate current thinking about the factors and mechanisms that contribute to failure in radiotherapy.