One-third of patients with aggressive non-Hodgkin lymphoma relapse after conventional chemotherapy and die of their disease. We need new methods to identify, at diagnosis, which patients have a high risk of relapse to improve their treatment. Genetic profiling is a powerful tool that can identify these high-risk patients. ‘Double-hit lymphoma’ (DHL) is one type of lymphoma that responds poorly to standard treatment. Current testing strategies cannot accurately identify all patients with DHL. We aim to improve the identification and treatment of DHL with a new test that uses a unique ‘genetic blueprint’. We will apply this test on lymphoma samples from 900 aggressive lymphoma patients in British Columbia to find out its ability to identify DHL patients compared to current methods. Patients who carry this genetic blueprint may benefit from different treatment approaches that overcome the high risk of relapse. We will also conduct an in-depth genetic analysis of DHL to understand how these lymphomas develop in the body. This new knowledge will help design smarter therapies that target the tumour while sparing normal body cells. These ‘targeted therapies’ can avoid the significant side effects caused by intensive chemotherapy.