My Capstone Project aimed at investigating the role of HER2 (Human Epidermal Growth Factor Receptor 2) as a resistance biomarker in breast cancer treatment.  The project focused on understanding how HER2-positive breast cancer develops resistance to targeted therapies such as trastuzumab (Herceptin), which specifically targets HER2.  While HER2 status serves as a valuable biomarker itself, additional biomarkers are essential to enhance the precision of predicting trastuzumab response.  Therefore the objective of the Capstone Project was to explore novel and emerging therapeutic options that have shown promise in enhancing treatment response in HER2-positive breast cancer patients. The findings were aimed to contribute to implementing more optimal treatment strategies customized for each individual patient’s requirements thereby optimizing therapy outcomes and ultimately saving lives.