? Shikha Jain, MD, FACP, felt the urgency of the moment. It was 10:00 AM. A young patient had stepped into her Chicago cancer clinic. His face was red, and he was struggling to breathe. The man had primary mediastinal B-cell lymphoma , a rare, aggressive form of non-Hodgkin lymphoma . Many cases involve large, fast‐growing masses that expand into the lungs and compress respiratory pathways , sometimes leaving patients breathless. Jain rushed to his side ...