Diego is 16 years old. He has been diagnosed Leukemia, a cancer affecting white blood cells. White blood cells are the natural defense your body to fight infections, and red Blood cells are formed in the bone marrow. However, with his leukemia the bone marrow produces abnormal white blood cells. These cells eventually replace the healthy blood cells and makes it difficult for normal blood to perform its function. And Acute Lymphocytic Leukemia is also called Acute Lymphoblastic Leukemia when there are too many white blood cells of a specific type called lymphocytes or lymphoblasts present in the immune system. This is the most common type of cancer for children that range from 5 years to 13 years of age. (Ref. Wikipedia)