precursor B-lymphoblastic leukemia

(pree-KER-ser B-LIM-foh-BLAS-tik loo-KEE-mee-uh) A type of leukemia (blood cancer) in which too many B-cell lymphoblasts (immature white blood cells) are found in the blood and bone marrow. It is the most common type of acute lymphoblastic leukemia (ALL). Also called B-cell acute lymphoblastic leukemia and B-cell acute lymphocytic leukemia.