Despite the statistical significance observed for an association between tumor expression levels of CEA, MRP2, TNF-a, and CXCR4 with patients’ OS time (Kaplan–Meier and univariate Cox regressions), an ROC curve analysis indicated a poor prognostic value for these markers when independently analyzed, given that the areas under the curves (AUC) were <0.75 (Figure 3D), a cut-off value for the clinically discriminatory power of the test [34]. The gene discussed is CXCR4; the disease is neoplasm.