AGR2 and breast cancer: AGR2 expression was most frequently seen in tumors of the female genital tract, particularly adenocarcinoma of the cervix (100%) and mucinous carcinoma of the ovary (100%), various subtypes of breast cancer (57.1%–100%), urothelial carcinoma (74.6%–100%), adenocarcinoma of the upper and lower gastrointestinal tract (93.6%–99.6%), as well as in pancreatico‐biliary cancers (65.2%–98.2%).