B-cell Acute Lymphoblastic Leukemia (B-ALL) is a type of cancer that originates in the bone marrow and is characterized by the overproduction of immature B-cell lymphoblasts, leading to impaired blood cell production and increased risk of infections. It is the most common form of leukemia in children, but it can also occur in adults, and is typically treated with chemotherapy, targeted therapy, and sometimes stem cell transplantation.