Upregulation of HOXA1 promotes tumorigenesis and development of non‑small cell lung cancer: A comprehensive investigation based on reverse transcription-quantitative polymerase chain reaction and bioinformatics analysis.

Homeobox A1 (HOXA1) serves an oncogenic role in multiple cancer types. However, the role of HOXA1 in non‑small cell lung cancer (NSCLC) remains unclear. In the present study, use of reverse transcription-quantitative polymerase chain reaction and the databases of The Cancer Genome Atlas (TCGA), Oncomine, Gene Expression Profiling Interactive Analysis and the Multi Experiment Matrix were combined to assess the expression of HOXA1 and its co-expressed genes in NSCLC. Bioinformatic analyses, such as Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and network and protein-protein interaction analyses, were used to investigate the underlying molecular mechanism effected by the co-expressed genes. Additionally, the potential miRNAs targeting HOXA1 were investigated. The results showed that HOXA1 was upregulated in NSCLC. The area under the curve of HOXA1 indicated a moderate diagnostic value of the HOXA1 level in NSCLC. According to GO and KEGG analyses, the co-expressed genes may be involved in 'dGTP metabolic processes', 'network-forming collagen trimers', 'centromeric DNA binding' and 'the p53 signaling pathway'. Three miRNAs (miR‑181b‑5p, miR‑28‑5p and miR‑181d‑5p) targeting HOXA1 were each predicted by 10 algorithms; miR‑181b and miR‑181d levels were downregulated in LUSC tissues compared with those in normal lung tissues based on data from the TCGA database, and inverse correlations were found between HOXA1 and miR‑181b (r=-0.205, P<0.001) and miR‑181d (r=-0.106, P=0.020). We speculate that HOXA1 may be the direct target of miR‑181b‑5p or miR‑181d‑5p in LUSC, and HOXA1 may serve a significant role in NSCLC by regulating various pathways, particularly the p53 signaling pathway. However, the detailed mechanism should be verified by functional experiments.