The ContraCancrum i.e. the Clinically Oriented Translational Cancer Multilevel Modelling project aims at developing a composite multilevel platform for simulating malignant tumour development and tumour and normal tissue response to therapeutic modalities and treatment schedules. The project aims at having an impact primarily in (a) the better understanding of the natural phenomenon of cancer at different levels of biocomplexity and most importantly (b) the disease treatment optimization procedure in the patient's individualized context by simulating the response to various therapeutic regimens. The predictions of the simulators to be developed will rely on the imaging, histopathological, molecular and clinical data of the patient. Fundamental biological mechanisms involved in tumour development and tumour and normal tissue treatment response such as metabolism, cell cycle, tissue mechanics, cell survival following treatment etc. will be modelled. Stem cells will be addressed in the context of both tumour and normal tissue behaviour. From the mathematical point of view the simulators will exploit several discrete and continuous mathematics methods such as cellular automata, the generic Monte Carlo technique, finite elements, differential equations, novel dedicated algorithms etc. A study of the analogies of tumour growth with embryological development is expected to provide insights into both mechanisms. ContraCancrum will deploy two important clinical studies for validating the models, one on lung cancer and one on gliomas. The crucial validation work will be based on comparing the multi-level therapy simulation predictions with the actual medical data (including medical images), acquired before and after therapy. ContraCancrum aims to pave the way for translating clinically validated multilevel cancer models into clinical practice.