Lymphomas are cancers that arise from lymphoid cells, which are part of the immune system. The World Health Organization currently recognizes about 70 different types of lymphoma and divides them into four major groups: mature B-cell neoplasms, mature T-cell and natural killer cell neoplasms, Hodgkin lymphoma, and immunodeficiency-associated lymphoproliferative disorders. Although Hodgkin lymphoma is a B-cell malignancy, it is characterized by an abnormal type of cell known as the Reed-Sternberg cell, which is not found in other types of B-cell lymphoma. Collectively, lymphomas represent about 5 percent of all cancers diagnosed in the United States. In 2012, it is estimated that 79,000 Americans will be diagnosed with lymphoma and 20,100 will die from the disease. Although lymphoma incidence rates have been stable over the past decade, lymphoma death rates have been declining steadily. These declines in mortality can be attributed to improvements in treatment. Today, the 5-year relative survival rate for all patients diagnosed with lymphoma is approximately 71 percent; for patients diagnosed with Hodgkin lymphoma, it’s about 85 percent. Indeed, Hodgkin lymphoma is now considered one of the most curable forms of cancer. Treatments for lymphoma include surgery, watchful waiting, chemotherapy, radiation therapy, and targeted therapy. The choice of treatment depends on the type and grade of the lymphoma, the stage of the disease, and the age and general health of the patient.