In order to enable the advent of personalized medicine, we need solid in vitro models, taking into account the 3D microenvironment of the tumor, the human component, and the vasculature, to test both the toxicity and efficacy of new molecules. Today, the drug screenings are performed on 3D cell lines models and Patient-Derived Xenografts models. These models are not able to recapitulate the whole tumor microenvironment and vasculature, with hopeless return to the patient. Here, we propose our in vitro model, based on Patient-Derived Organoids, in a vascularized 3D environment, including mesenchymal stem cells. We believe that this will greatly contribute to the development of personalized medicine, since we are working on both healthy tissue (toxicity) and tumor tissue (efficacy). The second step of this model will be the integration of immune cells based on recent discoveries.