DEK promotes the proliferation and invasion of lung cancers and indicates poor prognosis in lung adenocarcinomas.

DEK has been revealed to be overexpressed in many cancers and associated with cancer progression. The aim of the present study was to elucidate the role of DEK with a specific focus on its underlying mechanism in lung cancers. DEK expression in lung cancers and normal lung tissues and the correlations between DEK expression and clinicopathological parameters of lung cancers were investigated using the data from The Cancer Genome Atlas (TCGA). DEK expression was upregulated by DEK transfection or downregulated by DEK shRNA interference in A549 and H1299 cells. The effects of DEK on the Wnt signaling pathway and epithelial‑mesenchymal transition (EMT) were examined using western blotting. Proliferative and invasive abilities were observed in A549 and H1299 cells treated with DEK using an MTT assay, colony formation assay, and Transwell migration and invasion assays. The expression of DEK was higher in lung cancer tissues than that in normal lung tissues. DEK expression was positively correlated with the expression of epidermal growth factor receptor (EGFR) and KRAS in lung adenocarcinomas. High expression of DEK indicated poor prognosis in lung adenocarcinomas (P=0.018). Enhanced expression of DEK upregulated the levels of active‑β‑catenin and Wnt target genes, such as cyclin D1, c‑Myc and MMP7 and increased the proliferative and invasive abilities of lung cancer cells. Enhanced expression of DEK in A549 and H1299 cells also increased the levels of EGFR, KRAS, vimentin, Snail, and N‑cadherin, and decreased the level of E‑cadherin. The opposite results were obtained with knockdown of DEK expression. DEK was highly expressed in lung cancers and indicated poor prognosis in lung adenocarcinomas. DEK expression activated the Wnt signaling pathway and EMT process and promoted the proliferation and invasion of lung cancers.