[Hypermethylation of promoter region of RAS association domain family gene1A in esophageal squamous cell carcinoma and significance thereof].

OBJECTIVE: To investigate the hypermethylation of the promoter region of RAS association domain family gene1A (RASSF1A) and its relationship with esophageal squamous cell carcinoma.
METHODS: Sixty-six patients with esophageal squamous carcinoma, 60 males and 6 females, aged 59 +/- 8 (44 - 76), underwent resection of the tumor. Methylation-specific PCR (MSP) was used to detect the hypermethylation of promoter region of RASSF1A in the carcinoma tissues and the adjacent normal tissues.
RESULTS: The hypermethylation rate of RASSF1A promoter in the tumor tissues was 48. 5% (32/66), significantly higher than that in the adjacent normal tissues (6.1%, 4/66, P < 0.05). The hypermethylation rate of RASSF1A promoter of the patients with lymph node metastasis was 61.1%, significantly higher than that of the patients without lymph node metastasis (33.3%, chi(2) = 5.055, P = 0.025). The hypermethylation rate of RASSF1A promoter in the esophageal squamous cell carcinoma at advanced stages (stages III - IV) was 69.2%, significantly higher than that in the esophageal squamous cell carcinoma at early stages (stages I - II, 35.0%, chi(2) = 7.392, P = 0.007). The hypermethylation rates of RASSF1A promoter in the high, moderate, and low differentiation tumors were 61.5% (16/26), 46.2% (12/26), and 28.6% (4/14) respectively without significant differences among them (chi(2) = 4.053, P = 0.132).
CONCLUSION: Abnormal methylation exists in the RASSF1A promoter in esophageal squamous cell carcinoma. The hypermethylation of RASSF1A promoter is related to lymph node metastasis and TNM stage.