title: Dicentric (9;20)(p11;q11) identified by fluorescence in situ hybridization in four pediatric acute lymphoblastic leukemia patients.
abstract: Four children with acute lymphocytic leukemia (ALL) and a dic(9;20) are described. All four patients were diagnosed with pre-B-cell All, and the three for whom information was available were CD10+. Age at diagnosis ranged from 23 months to 12 years. All patients achieved remission, with two in continuous remission for 2 years 6 months and 3 years, one patient relapsed, dying 3 years 2 months after diagnosis, and one patient was lost to follow-up. These four patients were initially diagnosed as having a deletion of 9p and loss of one chromosome 20. Re-examination of the karyotypes indicated a possible dic(9;20). The dicentric chromosome was verified using dual-color fluorescence in situ hybridization (FISH) with centromeric probes for chromosomes 9 and 20 on interphase nuclei. Three of the four patients had multiple chromosomal abnormalities in addition to the translocation; one was hypodiploid, one was pseudodiploid, and two were hyperdiploid. This dicentric chromosome was recently described in four adult and nine pediatric patients with ALL [8, 9]. All reported patients had CD10+ pre-B-cell All, and achieved remission, as was the case for our four pediatric dic(9;20) patients. Two of our three patients for whom follow-up is available are in continuous remission as were two adults and five pediatric patients in the previous reports. These studies confirm the dic(9;20) as a recurring abnormality in ALL. Due to the subtle nature of the translocation, FISH is very useful in confirming the chromosomal abnormality.
authors.affiliation: Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis 46202-5251, USA.
authors.forename: N A
authors.initials: NA
authors.lastname: Heerema
authors.forename: K D
authors.initials: KD
authors.lastname: Maben
authors.forename: J
authors.initials: J
authors.lastname: Bernstein
authors.forename: P P
authors.initials: PP
authors.lastname: Breitfeld
authors.forename: R S
authors.initials: RS
authors.lastname: Neiman
authors.forename: G H
authors.initials: GH
authors.lastname: Vance
mesh_terms: D000328:Adult; D001853:Bone Marrow / Q000473:pathology; D002051:Burkitt Lymphoma / Q000235:genetics* / Q000401:mortality / Q000473:pathology / Q000628:therapy; D002503:Centromere / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations; D002872:Chromosome Deletion; D025063:Chromosome Disorders; D002874:Chromosome Mapping; D002890:Chromosomes, Human, Pair 20; D002899:Chromosomes, Human, Pair 9; D005500:Follow-Up Studies; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D007399:Interphase; D007621:Karyotyping; D015452:Precursor B-Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics* / Q000401:mortality / Q000473:pathology / Q000628:therapy; D013997:Time Factors; D014178:Translocation, Genetic