title: The gene expression signature of relapse in paediatric acute lymphoblastic leukaemia: implications for mechanisms of therapy failure.
abstract: Despite significant improvements in the treatment of childhood acute lymphoblastic leukaemia (ALL), the prognosis for relapsing patients remains poor. The aim of this study was to generate a transcriptional profile of relapsed ALL to increase our understanding of the mechanisms involved in therapy failure. RNA was extracted from 11 pairs of cryopreserved pre-B ALL bone marrow specimens taken from the same patients at diagnosis and relapse, and analysed using HG-U133A microarrays. Relapse specimens overexpressed genes that are involved with cell growth and proliferation, in keeping with their aggressive phenotype. When tested in 72 independent specimens of pre-B ALL and T-ALL, the identified genes could successfully differentiate between diagnosis and relapse in either lineage, indicating the existence of relapse mechanisms common to both. These genes have functions relevant for oncogenesis, drug resistance and metastasis, but are not related to classical multidrug-resistance pathways. Increased expression of the top-ranked gene (BSG) at diagnosis was significantly associated with adverse outcome. Several chromosomal loci, including 19p13, were identified as potential hotspots for aberrant gene expression in relapsed ALL. Our results provide evidence for a link between drug resistance and the microenvironment that has previously only been considered in the context of solid tumour biology.
authors.affiliation: Division of Children's Leukaemia and Cancer Research, Telethon Institute for Child Health Research, University of Western Australia, Perth, WA, Australia.
authors.forename: Alex H
authors.initials: AH
authors.lastname: Beesley
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Cummings
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Freitas
authors.forename: Katrin
authors.initials: K
authors.lastname: Hoffmann
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Firth
authors.forename: Jette
authors.initials: J
authors.lastname: Ford
authors.forename: Nicolas H
authors.initials: NH
authors.lastname: de Klerk
authors.forename: Ursula R
authors.initials: UR
authors.lastname: Kees
mesh_terms: D000293:Adolescent; D051926:Basigin / Q000235:genetics / Q000378:metabolism; D002051:Burkitt Lymphoma / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism; D002455:Cell Division / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007223:Infant; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000235:genetics; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism; D011379:Prognosis; D012008:Recurrence; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016019:Survival Analysis; D017211:Treatment Failure; D016896:Treatment Outcome
chemical_list: C497886:BSG protein, human; D009363:Neoplasm Proteins; D051926:Basigin