Non-Hodgkin's lymphoma is a type of cancer that originates in the lymphatic system, which is part of the body's immune system. It involves the uncontrolled growth of lymphocytes, a type of white blood cell. There are many subtypes of non-Hodgkin's lymphoma, and they can vary in how aggressive they are and how they respond to treatment. Symptoms of non-Hodgkin's lymphoma may include swollen lymph nodes, fever, night sweats, and unexplained weight loss. Diagnosis typically involves blood tests, imaging studies, and a biopsy of affected tissue. Treatment options may include chemotherapy, radiation therapy, and targeted therapies, depending on the specific type and stage of the disease.