Morphologic, immunologic and cytogenetic studies in children with acute lymphoblastic leukemia at diagnosis and relapse: A pediatric oncology group study

The morphologic, immunologic and cytogenetic features of leukemic cells obtained at the time of first bone marrow relapse were compared with those obtained at initial diagnosis in 287 children with acute lymphoblastic leukemia (ALL) who were entered consecutively in a laboratory classification study of the Pediatric Oncology Group (POG). L1 to L2 shifts in French American-British morphologic subtype were more common than the reverse (81/178 versus 15/61, p<0.001)