[Down-regulation of caveolin-1 in gastric carcinoma and its clinical biological significance].

BACKGROUND & OBJECTIVE: Caveolin-1, a candidate tumor suppressor gene, aberrantly expressed in many kinds of carcinomas. This research was designed to check the expression of Caveolin-1 in non-cancerous gastric mucosa, intestinal metaplasia, atypical hyperplasia, gastric cancer tissues, and gastric cancer cell lines MGC803 and BGC823, and to analyze its clinical biological significance in stepwise gastric carcinogenesis. METHODS: Frozen gastric tissue array-based immunohistochemistry (IHC) was used to examine the expression of Caveolin-1 in 56 specimens of gastric cancer, 29 specimens of non-cancerous mucosa, 11 specimens of intestinal metaplasia, and 7 specimens of atypical hyperplasia. Correlations of Caveolin-1 expression to clinical stage, lymph node metastasis, Lauren's type, and histological type were analyzed. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used to detect mRNA and protein levels of Caveolin-1 in 56 specimens of gastric cancer and relevant adjuvant non-cancerous tissue, and cell lines MGC803 and BGC823. RESULTS: Positive rate of Caveolin-1 was significantly lower in gastric cancer than in non-cancerous mucosa, intestinal metaplasia, and atypical hyperplasia (17.9% vs. 84.8%, 81.8%, and 57.1%, P<0.05). Positive rate of Caveolin-1 was lower in advanced gastric cancers than in gastric cancer of early stage (16.0% vs. 33.3%), but the difference was not significant (P>0.05). Positive rate of Caveolin-1 was significantly lower in diffuse gastric cancer than in gastric cancer of intestinal type (7.0% vs. 26.9%, P<0.05), significantly lower in the cases with lymph node metastases than in the cases without lymph node metastases (9.7% vs. 31.8%, P<0.05). Protein and mRNA levels of Caveolin-1 in gastric cancer and relevant adjuvant non-cancerous tissues have no significant difference, but its expression was low in MGC803 and BGC823 cells. CONCLUSION: Progressive down-regulation of Caveolin-1 in gastric epithelial cells is correlated to gastric carcinogenesis.