Abstract:

Background and purpose: As one of the important epigenetic phenomena, DNA methylation plays an important regulatory function for the expression of genes. Study shows that abnormal changes of DNA methylation patterns of normal tumor cell genome leads to dysfunction of cancer related gene, and this may be associated with tumor occurrence and development. The study investigated the promoter methylation and expression of caveolin-1 (CAV-1) gene in esophageal squamous cell carcinoma (ESCC), and to elucidate its role in ESCC. Methods: We used MSP approach, RT-PCR, and immunohistochemistry method respectively to examine the methylation status of the 5’CpG island of CAV-1 gene and its expression at mRNA and protein levels in tumors and corresponding normal tissues. Results: CAV-1 mRNA expression in tumor tissues (0.86±0.56) was significantly higher than that in corresponding normal tissues (0.40±0.36, P<0.05). The mRNA expression of CAV-1 was correlated with status of lymphatic metastasis and TNM stage of ESCC patients (P<0.05). The protein expression of CAV-1 in tumor specimens (66.7%, 34/51) was significantly higher than that in corresponding normal tissues (15.7%, 8/51, P<0.01). The protein expression of CAV-1 was significantly associated with lymphatic metastasis of ESCC (P<0.05), however, it was not associated with differentiation and TNM stage (P>0.05). The promoter methylation frequency of CAV-1 in tumor specimens was 2.0% (1/51), and the methylation phenomenon has not been found in corresponding normal tissues. The promoter methylation frequency of CAV-1 in tumor specimens showed no significant difference compared with the corresponding normal tissues (P>0.05). Conclusion: The mRNA and protein expression of CAV-1 in tumor specimens was significantly higher than that in corresponding normal tissues. Aberrant high expression of CAV-1 has played a certain role in promoting tumorigenesis and lymph node metastasis. The expression both in ESCC and corresponding normal tissues has no correlation with the promoter methylation status.

Key words: Esophageal squamous cell carcinoma, Methylation, CAV-1 gene, Expression