Non-Hodgkin lymphoma (NHL) is a cancer of a type of white blood cell called lymphocytes. Lymphocytes are part of the immune system that protects the body from infection and disease. NHL is a group of 30 or more cancers that begin in the lymphocytes.
These cancers are similar in some ways but have many differences in the way they affect people. They are all called non-Hodgkin lymphoma to distinguish them from another cancer of the lymphocytes called Hodgkin lymphoma.