A shift towards antibody-based cancer treatments has occurred due to their ability to provide targeted cancer treatment with fewer negative side effects than traditional chemotherapy or radiotherapy. Large antibody fusions with proteins that activate the human immune system to combat tumours have been developed with potent anti-tumour responses observed in preclinical models. The structure of a protein is key to understanding its function so we propose to study the shape, size and finer structure of a large fusion protein specifically designed to enable the immune system to destroy cancerous tissue. At its first ever SANS study, we will investigate how environmental conditions such as pH, temperature and salt concentration impact the structure of the aforementioned fusion protein. Understanding protein structure is vital in understanding why a protein is able to function.