Promoter CpG methylation of caveolin-1 in sporadic colorectal cancer.

BACKGROUND Caveolin-1 has been shown to be down-regulated in human colon cancer and involved in colon tumorigenesis. We investigated the mechanism. MATERIALS AND METHODS Cancerous and nearby non-cancerous tissues of 185 sporadic colorectal cancer samples were enrolled in this study. Methylation-specific PCR was performed to explore the mechanism of regulation of caveolin-1 gene expression. RESULTS Aberrant promoter methylation in the caveolin-1 gene was 3.8% and 5.9% for cancerous and nearby non-cancerous tissues, respectively. All the cancerous and non-cancerous tissue contained unmethylated promoters in the caveolin-1 gene. The methylation status of caveolin-1 had no clear relationship with age, cell grade, location of tumor or lymph node metastasis. However, female gender showed statistically significant difference (p=0.045). The immunohistochemistry study demonstrated that expression of caveolin-1 correlated with aberrant promoter methylation status in sporadic colorectal cancer tissues. CONCLUSION Our findings suggested that aberrant promoter methylation of the caveolin-1 gene may occur at the precancerous stage, regulated by gender-related factors and is associated with gene silencing of caveolin-1 in the development of colorectal cancer.