CDH13 and gonorrhea: Other studies have shown that tumor specific epigenetic silencing of cadherin 13, H-cadherin (CDH13) and cadherin 1, type1, E-cadherin (CDH1), alone or in combination, were involved in PA development and invasion [11], and CpG hypermethylation-mediated glutathione S-transferase pi gene (GSTP1) inactivation was a common finding in PAs potentially contributing to their invasive behavior [12].