In 2000, researchers discovered that the most common form of non-Hodgkin lymphoma (NHL), diffuse large B-cell lymphoma, is actually two distinct diseases, explaining why only 40 percent of patients with NHL can be cured by chemotherapy.

The two main types of lymphoma are called Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL). Hodgkin lymphoma was named after the doctor who first recognised it. It used to be called Hodgkin’s disease.