Therapeutic antibodies are a popular and effective class of cancer drugs, particularly when combined with more traditional treatments. While natural antibodies are found in our blood all the time, they do not recognize cancer. Therapeutic antibodies are designed to recognize special molecules found only on the surface of cancer cells, allowing them to target and kill those cells without harming healthy ones. This results in a dramatic decrease in the side effects of chemotherapy such as nausea, fatigue and hair loss. Little is known about how therapeutic antibodies work, including the reasons why they are ineffective in some cancer patients. This lack of knowledge currently makes it hard to adapt or improve the drugs. Jesse Popov is studying trastuzumab, a therapeutic antibody used to treat aggressive breast cancers. Focusing on revolutionary new theories about the way that cellular membranes function, Jesse is working to determine how trastuzumab works in the body, as well as the basis for trastuzumab resistance. With new insights, he hopes to uncover ways to tailor therapeutic antibody-containing pharmaceuticals to make them more effective in treating different forms of cancer. This research is part of the ongoing Breast Cancer Research Program at the BC Cancer Research Centre, an initiative focused on identifying pharmaceutically viable methods for improving the effectiveness of breast cancer treatment.