Cell State Dynamics and Tumorigenesis in Boolean Regulatory Networks

A major goal of complex system sciences is to formally describe and understand how the parts of a system integrate into a whole whose qualities (‘emergent properties’) cannot be understood by studying the parts in isolation, but are derived from the interaction of the parts within the context of the whole. This bridging of the ‘hierarchical levels of integration’ will gain particular practical relevance in biology as genomic scientists will have soon collected and categorized the molecular inventory (the parts) of the system ‘human being’ (the whole). Therefore, a formal description of the fundamental rules for the integration of genes and proteins into organismal function is necessary if the deluge of genomic data is to be translated into a conceptual understanding of the organism that should benefit our knowledge of ‘complex’ diseases like cancer. A first level of integration well established to give rise to emergent properties is the interaction of genes and proteins in small model circuits involving (non-linear) feedback regulation that give rise to multiple stable states (multistability).