[Deletion of OPCML gene and promoter methylation in ovarian epithelial carcinoma].

Objective: To investigate the expression of OPCML gene in ovarian epithelial carcinoma and determine the relationship between mRNA expression and methylation of their promoters.

Method: Twenty normal ovarian tissues and 89 ovarian epithelial tumor specimens (72 malignant, 17 benign), as well as 3 ovarian carcinoma cell lines (SKOV-3, CAOV3, and 3AO), were collected for detection of OPCML gene expression by reverse transcription-polymerase chain reaction and for detection of promoter methylation by restriction enzyme cut analysis from 7. 1999 to 7. 2003.

Results: Among ovarian epithelial carcinoma 19.4% expressed OPCML mRNA, while 85% of normal ovarian tissue and 76.5% of benign ovarian tumor. The ratio of expression of OPCML mRNA in ovarian epithelial carcinoma was significantly lower than those of normal (chi2 = 30.108, P = 0.0000) and benign tumors (chi2 = 21.162, P = 0.000). No OPCML mRNA expression was found in SKOV-3 and CAOV3, but was found in 3AO. Methylations were detected in 44.4% of cancer cells promoter, while 0% in normal ovarian tissue and benign ovarian tumors. The ratio of methylation of ovarian epithelial carcinoma was significantly higher than those of normal (chi2 = 13.630, P = 0.0000) and benign tumors (chi2 = 11.797, P = 0.000). Methylation was found in SKOV-3 and CAOV3, but not in 3AO. The relationship between gene expression and promoter methylation was correlated (r = 11.589, P = 0.002), especially at Hap I1 site (r = 11.640, P = 0.004). Methylation was also found in SKOV-3 and CAOV3 cell lines, but not in 3AO cell line.

Conclusion: Deletion of OPCML gene exists in ovarian epithelial carcinoma cell. The gene promoter methylations, especially Hap II motif, may be one of pathways that contribute the inhibition of OPCML expression.