Overexpression of TIM-4 promotes lung cancer cell growth and cell cycle progression. Cells were set up in 96- or 6-well plates. After grown to 80–90% confluence, A549 or NCI-H1975 cells were transfected with pc3 or pc3-hT4 plasmid DNA. After transfection, CCK-8 assay, cell cycle or protein analysis were performed at indicated time points. (A) The cell growth was monitored by CCK-8 assay for 7 days after transfection (*P<0.05, **P<0.01). (B) The TIM-4 mRNA was detected by RT–PCR on day 7 after transfection. (C) At 48 h after transfection, cell cycle analysis was performed by PI staining and flow cytometry. The represented graph of each group is indicated. (D) At 48 h after transfection, the protein expression of PCNA, cyclin A1, B1 and D1 was analysed by western blot. These experiments were repeated at least three times.