Expression of Plakophilins (PKP1, PKP2, and PKP3) in Gastric Cancers

Background: The importance of cell-cell junction proteins (including armadillo proteins) in tumor biology is known, but limited with regard to plakophilins. We explored the relationship between plakophilins (PKP1, PKP2, PKP3) to gastric cancer via immunohistochemical techniques. Methods: We compared the immunohistochemistry of PKPs in 34 gastric adenocarcinomas and 20 normal gastric tissues. Results: In gastric cancer, PKP1 expression was unchanged but PKP2 and PKP3 were significantly decreased as compared to normal controls. There was no observable clinical association with PKP1 or PKP2 expression; however, low PKP3 level and poor prognosis appeared to correlate with regards to node number and tumor stage. The mean disease-free survival (DFS) was 38 +/- 3 months (range: 32 - 44) and mean overall survival (OS) 42 +/- 4 months (range: 38 - 50). Decreased PKP2 appeared to negatively impact DFS. Conclusion: Decreased PKP2 and PKP3 may be early prognostic markers and loss of PKP3 expression during gastric carcinoma progression may indicate an invasive phenotype.