Associations between osteopontin expression, serum concentrations and patient outcome. A and B: Kaplan-Meier survival plots depicting relapse free survival based on tumor expression levels of OPN in the subgroup of patients with pTNM stage I and II (A) and in the subgroup of patients with adenocarcinomas (B). C: Box plots showing relative serum OPN concentrations according to tumor OPN expression levels. Since larger tumors are expected to secrete more OPN than small tumors given the same OPN expression levels, the serum OPN concentrations have been divided by tumor diameter. Data show median values (horizontal line within the box) and interquartile range (upper and lower border of the box) of serum OPN concentrations. The upper and lower horizontal bars represent the maximum and minimum values, respectively. Outliers have been removed from the plot. D: Kaplan-Meier survival plot depicting relapse free survival based on serum OPN level, patients dichotomized at the median OPN level. P-values calculated by one-way ANOVA test (C) and log-rank test (A, B, D).