Prognosis in acute lymphoblastic leukemia of childhood as determined by cytogenetic studies at diagnosis.

Fifty-one children with acute lymphoblastic leukemia on a common protocol of treatment were classified according to presence or absence of chromosomal abnormalities found at the time of diagnosis in bone marrow and/ or blood. Twenty-two or 43% had normal karyotypes while 29 (57%) had clonal abnormalities using the Giemsa-trypsin banding technique. Thirteen of the 29 (45%) chromo-somally abnormal patients relapsed while only three of 21 (14%) with normal karyotypes have relapsed with a median follow-up of 49.5 months (42-76 months). (One child with a normal karyotype did not respond to therapy.) Several hypotheses have been offered to attempt to explain the significantly better prognosis of patients with no observable initial chromosomal aberrations.