Sogawa et al. [40] found that C4BPA levels were significantly increased in PDAC patients compared to healthy controls/patients with pancreatitis/patients with other malignancies, including biliary tract cancers (p < 0.001), with an AUC of 0.860 for C4BPA and AUC of 0.930 for the combination C4BPA with CA19-9 in PDAC versus healthy controls (non-cancer patients). This evidence concerns the gene C4BPA and biliary tract cancer.