Then, Ankeny et al. used KRAS mutation analysis to compare CTCs with primary tumor tissue: promising results revealed CTCs as a good diagnostic tool for PC (sensitivity = 75.0%, specificity = 96.4%, area under the curve (AUROC) = 0.867, 95% CI = 0.798–0.935, and p < 0.001) with a cut-off of ≥3 CTCs in 4 mL of venous blood to discriminate between local/regional and metastatic disease (AUROC = 0.885; 95% CI = 0.800–0.969; and p < 0.001) [181]. This evidence concerns the gene KRAS and metastatic neoplasm.