Regarding survival analyses, OS was defined as the time from the date of surgery to the date of death or lost to follow-up. Kaplan-Meier estimates of the survival function, including P values from the log-rank test, were used to graphically compare the time-to-event outcomes based on ITGA5 expression and to estimate median OS. Furthermore, univariate and multivariate survival analyses were performed using the Cox proportional hazard regression model. Next to age and gender, only variables that were significant in univariate analysis were included in multivariate analyses, with an exception for primary tumor stage for OS (SPSS Statistical Software, version 23.0; IBM SPSS Inc., Chicago, IL). Group data are presented as means ± SEM for at least three independent experiments. The graphs and statistical analyses were performed using GraphPad Prism version 5.02 (GraphPad Prism Software Inc., La Jolla, CA). Statistical analysis of the results was performed by either a two-tailed unpaired Student’s t test for comparison of two treatment groups or a one-way analysis of variance (ANOVA) to compare multiple treatment groups. In all cases, differences were considered significant at P < 0.05.