In OVCA433 ovarian cancer cells and in MDCK I cells, expression of a mutant claudin-3 (barrier-forming claudin) that mimics cAMP-mediated phosphorylation of claudin-3 on threonine 192 (T192D) decreased TER (increased Pore Pathway permeability) and increased the permeability to 4 kDa fluorescein-dextran [125]. Here, CLDN3 is linked to ovarian cancer.