Expression of Reg Ia protein in human gastric cancers

Background/Aims: Although regenerating gene (Reg) Ialpha protein has a trophic effect on gastric epithelial cells, it is unclear whether Reg Ialpha protein and its receptor are involved in gastric carcinogenesis. Therefore, we investigated the Reg Ialpha protein expression in human gastric cancers and assessed its relationship to clinicopathological factors. Methods: Sixty-one gastric cancer specimens were examined, using immunohistochemistry, for Reg Ialpha protein, p53, and proliferating cell nuclear antigen. The expression of both Reg Ialpha and Reg receptor mRNA was examined in seven human gastric cancer cell lines (MKN1, MKN28, MKN45, MKN74, KATOIII, GCIY, and AGS) by reverse transcription-polymerase chain reaction and Northern blot analysis. Results: Twenty-three (37.7%) of the 61 gastric cancer tissues samples were positive for Reg Ialpha protein. The Reg Ialpha expression was significantly related to the presence of lymphatic invasion but not to tumor size, tumor stage, Lauren's classification, presence of venous invasion, lymph node metastases, or p53 overexpression. Gastric cancers positive for Reg Ialpha protein showed a significantly higher proliferating cell nuclear antigen labeling index than negative ones. The expression of both Reg Ialpha and Reg receptor mRNA was detected in all seven gastric cancer cell lines. Conclusion: Reg Ialpha protein may play a role in the development of gastric cancers. Copyright (C) 2004 S. Karger AG, Basel.