Tumor progression, dissemination, and therapy resistance depend on the complex crosstalk between cancer cells and the tumor microenvironment. This research group focuses on tumor–stroma interactions in glioblastoma (GBM) and breast cancer, particularly the role of astrocytes and cancer-associated fibroblasts (CAFs) in modulating tumor invasion, vascular-like structures formation and resistance to targeted therapies in 3D models. The team aims to develop advanced 3D platforms and matrices to study the effects of our recently developed cyclic peptides and novel combination treatments on GBM and breast cancer spheroids in the presence of human astrocytes or CAFs, respectively.