Blood cancer is leukemia. Leukemia is not an infectious disease and is not contagious, so leukemia is not contagious. Leukemia is the most common malignant tumor of the blood system. It is caused by the massive proliferation of leukemia cells in bone marrow, which leads to the destruction of normal hematopoietic function and the inability to produce red blood cells, white blood cells and platelets normally, and the patient will suffer from a series of symptoms, such as anemia, infections and bleeding. The reason why it is said that blood cancer is not an infectious disease is that a large number of clinical observations have found that healthcare workers or escorts who are in close contact with blood cancer patients do not get sick because of their close contact with blood cancer patients. At the same time, clinical tests have also found that injecting blood cells of patients with blood cancer into normal healthy human bodies will not transmit the disease because the immune system of normal human beings will eliminate all the cancer cells that have entered the human body, so blood cancer is not contagious.