Gene expression profiles predictive of outcome and age in infant acute lymphoblastic leukemia: a Children's Oncology Group study
ABSTRACT Gene expression profiling was performed on 97 cases of infant ALL from Children's Oncology Group Trial P9407. Statistical modeling of an outcome predictor revealed 3 genes highly predictive of event-free survival (EFS), beyond age and MLL status: FLT3, IRX2, and TACC2. Low FLT3 expression was found in a group of infants with excellent outcome (n = 11; 5-year EFS of 100%), whereas differential expression of IRX2 and TACC2 partitioned the remaining infants into 2 groups with significantly different survivals (5-year EFS of 16% vs 64%; P < .001). When infants with MLL-AFF1 were analyzed separately, a 7-gene classifier was developed that split them into 2 distinct groups with significantly different outcomes (5-year EFS of 20% vs 65%; P < .001). In this classifier, elevated expression of NEGR1 was associated with better EFS, whereas IRX2, EPS8, and TPD52 expression were correlated with worse outcome. This classifier also predicted EFS in an independent infant ALL cohort from the Interfant-99 trial. When evaluating expression profiles as a continuous variable relative to patient age, we further identified striking differences in profiles in infants less than or equal to 90 days of age and those more than 90 days of age. These age-related patterns suggest different mechanisms of leukemogenesis and may underlie the differential outcomes historically seen in these age groups.
SourceAvailable from: Ildiko Grandal[Show abstract] [Hide abstract]
ABSTRACT: During V(D)J recombination of immunoglobulin genes, p53 and nonhomologous end-joining (NHEJ) suppress aberrant rejoining of DNA double-strand breaks induced by recombinase-activating genes (Rags)-1/2, thus maintaining genomic stability and limiting malignant transformation during B-cell development. However, Rag deficiency does not prevent B-cell leukemogenesis in p53/NHEJ mutant mice, revealing that p53 and NHEJ also suppress Rag-independent mechanisms of B-cell leukemogenesis. Using several cytogenomic approaches, we identified a novel class of activating mutations in Fms-like tyrosine kinase 3 (Flt3), a receptor tyrosine kinase important for normal hematopoiesis in Rag/p53/NHEJ triple-mutant (TM) B-cell leukemias. These mutant Flt3 alleles were created by complex genomic rearrangements with Moloney leukemia virus (MuLV)-related endogenous retroviral (ERV) elements, generating ERV-Flt3 fusion genes encoding an N-terminally truncated mutant form of Flt3 (trFlt3) that was transcribed from ERV long terminal repeats. trFlt3 protein lacked most of the Flt3 extracellular domain and induced ligand-independent STAT5 phosphorylation and proliferation of hematopoietic progenitor cells. Furthermore, expression of trFlt3 in p53/NHEJ mutant hematopoietic progenitor cells promoted development of clinically aggressive B-cell leukemia. Thus, repetitive MuLV-related ERV sequences can participate in aberrant end-joining events that promote development of aggressive B-cell leukemia.Genes & Development 06/2014; 28(11):1179-90. DOI:10.1101/gad.240820.114 · 12.64 Impact Factor
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ABSTRACT: Osteosarcoma is the most common type of human primary malignant bone tumor with a potential propensity for local invasion and distant metastasis. Thus, this study focused on the expression and roles of IRX2 in the development of osteosarcoma. The mRNA expression levels of IRX2 in tissue samples of 69 cases of human osteosarcoma were detected by a quantitative polymerase chain reaction assay. The associations between the expression levels of IRX2 and the pathological features of the tumor tissues were analyzed. Functional studies were performed by MTT and Matrigel invasion assays following IRX2 knockdown with a lentivirus vector. Western blotting was used to assay the protein expression levels of IRX2, p‑AKT and matrix metalloproteinases (MMP). The results revealed that the expression levels of IRX2 were significantly increased in the primary human osteosarcoma tissues compared with those in the normal tissues, and the increase was significantly correlated with the tumor progression and prognosis of the patients. Furthermore, the proliferation and invasion of the cells were suppressed following IRX2 knockdown. Additionally, the mechanism by which IRX2 promoted cell proliferation and invasion by activating AKT and MMP9 was detected. In conclusion, these results indicated that IRX2 promotes proliferation and invasion in osteosarcoma and implicated the potential of IRX2 in cancer therapy.Molecular Medicine Reports 05/2014; 10(1). DOI:10.3892/mmr.2014.2215 · 1.48 Impact Factor
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ABSTRACT: The Tumor protein D52 (TPD52) gene was identified nearly 20 years ago through its overexpression in human cancer, and a substantial body of data now strongly supports TPD52 representing a gene amplification target at chromosome 8q21.13. This review updates progress toward understanding the significance of TPD52 overexpression and targeting, both in tumors known to be characterized by TPD52 overexpression/amplification, and those where TPD52 overexpression/amplification has been recently or variably reported. We highlight recent findings supporting microRNA regulation of TPD52 expression in experimental systems and describe progress toward deciphering TPD52's cellular functions, particularly in cancer cells. Finally, we provide an overview of TPD52's potential as a cancer biomarker and immunotherapeutic target. These combined studies highlight the potential value of genes such as TPD52, which are overexpressed in many cancer types, but have been relatively understudied.Tumor Biology 05/2014; 35(8). DOI:10.1007/s13277-014-2006-x · 2.84 Impact Factor