It is also worth noting that the majority of the studies for HER2-targeted therapy have focused on breast and gastric cancers and, according to the findings of Yan et al., the incidences of HER2-positivity in bladder, gallbladder, cholangiocarcinomas (extrahepatic), and esophageal and esophagogastric junction cancers were relatively high compared to breast and stomach cancers, implying that these oncotypes may also benefit from HER2-targeted therapies and that they should be considered for the clinical trials of these therapies [30]. Here, ERBB2 is linked to cholangiocarcinoma.