Among B-ALL, 42% were positive for the aberrantly expressed myeloid marker, CD66c, together with CD34 and CD10 (21/50), 10% with CD34+/CD10+/CD66c– (5/50), 6% CD34+/CD10– (3/50) and 32% CD34–/CD10+ (16/50). This evidence concerns the gene CD34 and acute lymphoblastic leukemia.