This project will validate the 3D in vitro starPEG-heparin hydrogel model as a physiologically relevant model that can screen for antineoplastic breast cancer therapeutics. It is hypothesized that the 3D in vitro model is physiologically precise enough as a model for mimicking the breast tumour microenvironment that it will accurately act as a platform for BCa drug screening. If the model does present itself as a tool capable of being used in drug-related research, then it may be used by clinicians as a drug screening tool within the clinic, or by researchers and pharmaceutical companies to develop novel drugs or elucidate potential synergistic behaviours between current drugs for breast cancer.