SLC29A1 and biliary tract neoplasm: In contrast, our meta-analysis of immunohistochemical biomarkers in patients with biliary tract cancers treated with gemcitabine-based chemotherapy, including 26 studies involving 1,348 patients with resected or advanced biliary tract cancers, showed the opposite trend: higher levels of hENT1 expression were associated with longer OS and disease-free/progression-free survival (Belkouz et al., 2019).