Identification of hub genes and molecular mechanisms in infant acute lymphoblastic leukemia withMLLgene rearrangement

Infant acute lymphoblastic leukemia (ALL) with the mixed lineage leukemia ( MLL ) gene rearrangement ( MLL -R) is considered a distinct leukemia from childhood or non- MLL -R infant ALL. To detect key genes and elucidate the molecular mechanisms of MLL -R infant ALL, microarray expression data were downloaded from the Gene Expression Omnibus (GEO) database, and differentially expressed genes (DEGs) between MLL -R and non- MLL -R infant ALL were identified. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were carried out. Then, we constructed a protein-protein interaction (PPI) network and identified the hub genes. Finally, drug-gene interactions were mined. A total of 139 cases of MLL -R infant ALL including 77 (55.4%) fusions with AF4 , 38 (27.3%) with ENL , 14 (10.1%) with AF9 , and 10 (7.2%) other gene fusions were characterized. A total of 236 up-regulated and 84 down-regulated DEGs were identified. The up-regulated DEGs were mainly involved in homophilic cell adhesion, negative regulation of apoptotic process and cellular response to drug GO terms, while down-regulated DEGs were mainly enriched in extracellular matrix organization, protein kinase C signaling and neuron projection extension GO terms. The up-regulated DEGs were enriched in seven KEGG pathways, mainly involving transcriptional regulation and signaling pathways, and down-regulated DEGs were involved in three main KEGG pathways including Alzheimer’s disease, TGF-beta signaling pathway, and hematopoietic cell lineage. The PPI network included 297 nodes and 410 edges, with MYC , ALB , CD44 , PTPRC and TNF identified as hub genes. Twenty-three drug-gene interactions including four up-regulated hub genes and 24 drugs were constructed by Drug Gene Interaction database (DGIdb). In conclusion, MYC , ALB , CD44 , PTPRC and TNF may be potential bio-markers for the diagnosis and therapy of MLL -R infant ALL.