Spss 22.0 statistical program

Colony formation assays. Cells were cultivated in 6-well culture plates at a density of 1000 cells/well after transfecting CtBP2-shRNA and control shRNA. After 2 weeks, cell colonies (≥50 cells/colony) were counted by staining with a 0.5% crystal violet solution.
Wound healing assay. The migration ability of cells was measured using in vitro wound-healing assay. Cells were seeded into six-well plates and prepared until 80% growth confluence in a monolayer. Cells were serum starved for 12 h after 36 h transfection with control-shRNA, CtBP2-shRNA. Wounds were afflicted by scraping the monolayer cells with a sterile 100 µl pipette tip. At 0, 12 and 24 h after wounding, cells were observed under the inverted Leica phase-contrast microscope (Leica DFC 300 FX) to measure the distance between the two wounds at each time point and present the average percentage wound closure compared to that noted at zero time.
Statistical analysis. Statistical analysis was conducted by SPSS 22.0 statistical program. The expression of CtBP2 and clinical-pathological features was analyzed by 2 tests. Survival curves were obtained by the Kaplan-Meier method and analyzed by log-rank test. Multivariate analysis was performed using Cox's proportional hazards model. Values were expressed as mean ± SEM and p<0.05 was considered statistically significant.