TFF1 and breast cancer: Our data show that TFF1 positivity occurs most commonly in mucinous carcinomas of the ovary, colorectal adenocarcinomas, breast cancer, bilio-pancreatic, and gastro-esophageal adenocarcinomas, neuroendocrine neoplasms, adenocarcinomas of the cervix uteri, and in urothelial neoplasms.