Age Specific Distribution Of Cytogenetic Subgroups Of Acute Myeloid Leukemia

Objective: To observe age distribution of different cytogenetic subgroupsin order to find the relationship between age and cytogenetics of acute myeloidleukemia （AML）.Methods: Between January of2004and December of2011640patientsof de novo AML were enrolled in this study.358cases were male, and282cases were female. The median age was41years （ranged from9months to83years）. From the view of FAB （French-American-British） classification,7caseswere M₀;16cases were M₁;265cases were M₂;187cases were M₃;88caseswere M₄;66cases were M₅;10cases were M₆; and only1case was M₇. Theanalyses were performed according to standard culturing and bandingtechniques, and clonal abnormalities were defined and described according tothe International System for Human Cytogenetic Nomenclature. Thecytogenetically grouping was performed as normal, balanced, and unbalancedkaryotype. In order to observe the age distribution of the subtypes, we analyzedthe distribution of complex karyotype, monosomal karyotype and othersubgroups in unbalanced karyotype group. The patients were divided into eightage groups,0-9,10-19,20-29,30-39,40-49,50-59,60-69,≥70years oldaccording to age factor.Results: Based on cytogenetic classification, the640patients weredivided into3large groups:40.0%（256/640） had normal karyotypes,43.13%（276/642） had balanced karyotypes, and the remaining16.88%（108/642） hadunbalanced karyotypes. Within the balanced karyotype group, there were163patients with t（15;17）（q22;q21）,97with t（8;21）（q22;q22）,8with inv（16）（p13;q22）, and the incidence rate were25.47%,15.16%and1.25%, respectively. Inunbalanced group,3.59%（23/640） had complex karyotypes;2.03%（13/640） had monosomal karyotypes; only6cases （0.94%） were monosomy7. We alsofound2.81%of patients were trisomy8. The distribution of normal, balanced,unbalanced and complex karyotype showed age specific characteristics.Normal karyotype was increasing from6.67%to58.33%（χ²=20.68, P=0.001）and balanced karyotype was decreasing from73.33%to11.11%with ages（χ²=48.22, P<0.001）. From10-19age group to≥70age group, occurrence ofunbalanced karyotype was increased from3.39%to30.57%（χ²=18.92,P=0.004）. From20-29age group to≥70age group, occurrence of complexkaryotype was increased from0%to11.11%（χ²=16.41, P=0.012）. No agespecific distribution was observed in monosomal karyotype subgroups（P=0.311）.Conclusion: The different age profiles of the cytogenetic subtypes mayindicate the different mechanisms of the pathogenesis of AML, which may alsooffer beneficial information for etiological research and prevention of thedisease.