CLDN3 and adenocarcinoma: CLDN3 positivity was most seen in adenocarcinomas (67–100%) and neuroendocrine neoplasms (92–100%) from various organs as well as in other tumors of the female genital tract such as in various subtypes of ovarian and endometrial carcinoma (up to 100%) and different subtypes of breast cancer (95.3–100%).