Since cancer is a complex phenomenon that incorporates events occurring on differentlength and time scales, therefore multiscale models are needed if we hope to adequately addresscancer specific questions. In this paper we present three different multiscale individual-cell-basedmodels, each motivated by cancer-related problems emerging from each of the spatial scales: extracellular,cellular or subcellular, but also incorporating relevant information from other levels.We apply these hybrid models to investigate the influence of the microenvironement on tumourinvasion, cell-cell collaboration and competition leading to the initiation and growth of epithelialtumours, and to evolution of cell phenotypes/genotypes arising in tumours growing in differentoxygen concentrations. We also discuss how these models relate to one another and can be used tobridge biological scales relevant to cancer.
