Flow cytometric DNA index and karyotype in childhood lymphoblastic leukemia

Article type: Research Article

Authors: Forestier, Erik | Holmgren, Gösta | Roos, Göran^;

Affiliations: Department of Pediatrics, Umeå University, Sweden | Department of Clinical Genetics, Umeå University, Sweden | Department of Pathology, Umeå University, Sweden

Note: [] Correspondence: Göran Roos, Department of Pathology, Umeå University, S‐901 85 Umeå, Sweden. Tel.: +46 90 785 1801; Fax: +46 90 785 2829; E‐mail: [email protected].

Abstract: Flow cytometric DNA‐index (DI^{\rm FCM}) and karyotype were analysed in 82 consecutive children with acute lymphoblastic leukemia (ALL) during a 10 year period. A statistically significant correlation existed between modal chromosome number and DI^{\rm FCM} (p=0.009). DI^{\rm FCM} could reliably identify leukemias with >51 chromosomes, whereas only three out of 12 cases with modal chromosome numbers between 47–51 were classified as aneuploid by DI^{\rm FCM}. In the pseudodiploid group only one out of 20 leukemias had a DI^{\rm FCM}>1.0. Five leukemias with a diploid karyotype showed an aneuploid DI^{\rm FCM} and in three patients the flow cytometric measurement revealed biclonality undetected by karyotyping. During treatment aneuploid clones could be detected by DI^{\rm FCM} in a substantial number of cases where the cytogenetic analysis was normal, and the opposite was also demonstrated in one case. DI^{\rm FCM} gave prognostic information, showing that cases with a DI >1.12 (corresponding to 51 chromosomes) had a superior outcome with treatment protocols today in use.

Keywords: Lymphoblastic leukemia, childhood, flow cytometry, DNA‐index, karyotype, event free survival

Journal: Analytical Cellular Pathology, vol. 17, no. 3, pp. 145-156, 1998