Additionally, claudin-4 is highly expressed in ovarian tumor cell lines categorized in each of the five different molecular subtypes of epithelial ovarian cancer recently described by Tan and colleagues, which includes epithelial- [OVCA429, CaOV3], mesenchymal- [PEO1, SKOV3], and stem-like [OVCAR3, OVCAR5] subtypes [16–18]. Here, CLDN4 is linked to ovarian neoplasm.