CLDN18 and posterior cortical atrophy: Treatment with the protein kinase C (n-PKC) activator, 12-O-tetradecanoylphorbol 13-acetate (TPA), significantly induced claudin-18.2 mRNA expression in all the PCa cell lines and human telomerase reverse transcriptase (hTERT)-human pancreatic ductal epithelial (HPDE) cells in the pancreas.