title: The incidence peaks of the childhood acute leukemias reflect specific cytogenetic aberrations.
abstract: The correlation between age and karyotype was studied in 1425, 0 to 14.9 years old children who were diagnosed with acute lymphoblastic leukemia (ALL) or acute myeloblastic leukemia. Almost 80% of the non-Down B-cell precursor ALL cases in the 2 to 7 years frequency peak group who had aberrant cytogenetic results had either a high-hyperdiploid clone (51 to 61 chromosomes) or a translocation t(12;21)(p13;q22). Among B-cell precursor ALL cases, high white blood cell counts correlated with earlier age at diagnosis (rS=-0.23; P<0.001) being most evident for 11q23/MLL-aberrations, translocation t(12;21)(p13;q22), and high-hyperdiploidy. Among acute myeloblastic leukemia patients, frequency peaks were found for those with MLL/11q23 rearrangements (peak: first year), Down syndrome (peak: second to third year), or cytogenetic abnormalities other than translocations t(8;21), t(15;17), and inv(16)/t(16;16) (peak: first to third year). The epidemiology of the cytogenetic subsets of acute leukemias questions whether age as a disease-related prognostic parameter has any relevance in childhood leukemia clinical research beyond being a surrogate marker for more important, truly biologic features such as cytogenetic aberrations and white cell count at diagnosis. Further research is needed to explore whether the 2 to 7 years age incidence peak in childhood ALL harbor yet unidentified cytogenetic subsets with the same natural history as the high-hyperdiploid and t(12;21)-positive leukemias.
authors.affiliation: Department of Clinical Sciences, Pediatrics, University of Umeå, Sweden, and Pediatric Clinic II, The University Hospital Rigshospitalet, Copenhagen, Denmark.
authors.forename: Erik
authors.initials: E
authors.lastname: Forestier
authors.forename: Kjeld
authors.initials: K
authors.lastname: Schmiegelow
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations; D015331:Cohort Studies; D015897:Comorbidity; D020732:Cytogenetic Analysis / Q000379:methods; D004314:Down Syndrome / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007621:Karyotyping; D015470:Leukemia, Myeloid, Acute / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D008297:Male; D011003:Ploidies; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D012008:Recurrence; D012042:Registries / Q000706:statistics & numerical data; D012307:Risk Factors; D012537:Scandinavian and Nordic Countries / Q000453:epidemiology