Multiple model simulation: modelling cell division and differentiation in the prostate

We describe an approach to building a hybrid multi-scale model, using a Petri net model for the top layer, and object-oriented models at the lower layers, with a rigorous definition of how the layers compose. We apply this approach to building a model of prostate cell division and differentiation, with each model layer describing the processes at a suitable level of abstraction. This provides a systematic modular approach to modelling and to model validation, allowing use of diverse modelling techniques in developing multi-scale models with no loss of rigour or validity. We use this prostate model to develop a prototype simulation, and demonstrate that it is capable of simulating biologically-relevant numbers of cells.