Z Gastroenterol 2004; 42 - 59
DOI: 10.1055/s-2004-826960

Differential expression of caveolin-1 in gastric cancer cells and adjacent non-epithelial tissue

M Juhász 1, J Chen 2, J Hoffmann 2, C Röcken 3, H Schulz 4, Z Tulassay 1, P Malfertheiner 2, M Ebert 2
  • 12nd Department of Medicine, Faculty of Medicine, Semmelweis University, Budapest, Hungary
  • 2Department of Gastroenterology, Hepatology and Infectious Diseases
  • 3Institute of Pathology
  • 4Department of General Surgery, Otto-von-Guericke University, Magdeburg, Germany

Background and aims: The role of caveolin-1 in gastric cancer is currently unknown. Our aim was to investigate the expression pattern of caveolin-1 in gastric cancer, and its putative role in carcinogenesis.

Methods: Tissue samples (tumor and non-neoplastic gastric tissue) were obtained from 60 patients with gastric cancer. Transcription and expression of caveolin-1 was studied by quantitative RT-PCR, Western blotting, and immunohistochemistry. The P132L mutation was analyzed with RFLP. Hypermethylation of the promoter region was evaluated with 5-aza-2'-deoxycytidine treatment. In 27 patients, we analyzed the association of caveolin-1 expression in the non-epithelial compartment with clinicopathological features.

Results: Caveolin-1 mRNA levels were decreased in 14 (74%) of 19 gastric cancers compared to non-neoplastic tissue. The P132L mutation, previously described in breast cancer, was undetectable. No hypermethylation of the promoter region of the caveolin-1 gene could be identified. Both gastric cancer and matched non-neoplastic mucosa expressed caveolin-1, as demonstrated by Western blotting of tissue homogenates, while immunohistochemistry localized caveolin-1 in 41 gastric cancer specimens. However, cancer cells of only three (7%) patients expressed caveolin-1. Caveolin-1 was mainly expressed in the non-epithelial compartment (e.g. myocytes, fibroblasts, endothelial cells). Caveolin-1 expression was more common in the non-epithelial compartment of well-differentiated tumors than in that of undifferentiated and metastatic gastric cancers.

Conclusions: We demonstrate that the expression of caveolin-1 is lost frequently in gastric cancer cells and is only retained in the non-epithelial compartment of well-differentiated cancers.