Signalling pathways and gene regulation are critically involved in cellular decisions how to respond to external signals and are often perturbed in tumour development. While the processes have classically been studied on the level of cell populations the focus has shifted to single cell investigations in the last years. This allowed a very detailed view revealing not only a wide range of dynamic phenomena but also the heterogeneity between cells.

In this talk I will discuss gene expression and protein synthesis at the interface of cell population and single cell data and introduce a method for advanced differential gene expression analysis that takes the role of the cell cycle in proliferating cell populations into account. Moreover, I will demonstrate how single cell data can be used to derive a quantitative signalling models and to decipher the cross-talk between signalling pathways involved in genotoxic stress.