What causes leukemia and what are its early symptoms?

Leukemia is a group of malignant disorders caused by the abnormal proliferation of leukemic cells in the bone marrow or lymphatic system. Early symptoms vary depending on the type of disease and individual differences, with common manifestations including: 1. Progressive anemia, leading to weakness, fatigue, and dizziness; 2. Easy bleeding, such as nosebleeds, gum bleeding, and subcutaneous hemorrhage; 3. Systemic symptoms like fever, night sweats, weight loss, and joint pain; 4. Organ enlargement, such as swollen lymph nodes, hepatomegaly, and splenomegaly; 5. Skin petechiae and ecchymoses. If these symptoms occur, prompt medical attention is necessary, especially in cases of progressive anemia, frequent bleeding, or unexplained fever.