System Dynamics modeling of tumor growth: a possible tool for optimization of pharmacological treatment?

Process-based modeling has been widely used to simulate the behavior of all kinds of biological systems. Recent modeling studies on plants, proposed a new concept of autotoxicity as a main driver, along environmental gradients, of plant systems development (Mazzoleni et al., 2010). The release of autotoxic compounds was showed to be responsible for the generation of ring-like spatial patterns of individual plants, presenting an increase of dead biomass in their central growth zone (Cartenì et al., 2012). This has been recently associated to the levels of washing out of turnover products, showing that the occurrence of spatial patterns is dependent on the balance between positive and negative feedbacks by nutrients and toxic products respectively (Marasco et al., 2013). In oncology, simulation modeling was used to understand and predict tumor growth and also to anticipate the effects of different therapies (Anderson and Quaranta, 2008). In this work we discuss the possible application of the autotoxicity hypothesis on modeling the growth of solid tumors. In particular, simulations are implemented showing the development and the spatial arrangement, in relation to different levels of vascularization, of 3 different layers: (i) proliferating, (ii) quiescent and (iii) necrotic cells