Diffuse Large B-Cell Lymphoma (DLBCL) is a type of lymphoma, which is a cancer of the lymphatic system. It is the most common subtype of non-Hodgkin lymphoma (NHL), accounting for about 30-40% of all NHL cases. DLBCL arises from B-cells, a type of white blood cell that plays a crucial role in the immune system. The disease is characterized by rapidly growing masses of lymphoid tissue, often in lymph nodes but also in other organs.