T-Cell Leukemia is a type of cancer that affects the T-cells, which are a crucial part of the immune system. These cells help the body fight infections, but in T-Cell Leukemia, they grow uncontrollably. This can lead to a decrease in healthy blood cells, causing symptoms like fatigue, fever, and frequent infections. There are different subtypes of T-Cell Leukemia, including Acute T-Cell Lymphoblastic Leukemia and Peripheral T-Cell Lymphoma. Diagnosis typically involves blood tests, bone marrow biopsies, and imaging studies. Treatment options may include chemotherapy, radiation therapy, and stem cell transplants, depending on the specific type and stage of the disease.