Promoter Methylation Of RASSF1A Gene And Its Correlation With DNMT1Expression In Esophageal Squamous Cell Carcinoma

Objective: We aimed to detect methylation of RASSF1A gene promoterand the expression of protein DNMT1in esophageal cancer tissue, and discusstheir relationship with esophageal squamous cell carcinoma.Methods: The CpG island methylation status of RASSF1A genes wereanalyzed in100cases of tumor specimens and their adjacent tissues usingMethylation-specific polymerase chain reaction(MSP).DNMT1Proteinexpression were determined by immunohistochemistry in100cases ofesophageal tumor specimens and their adjacent tissues.Results: The promoter methylation of RASSF1A gene promoter has beendetected in45of100(45%) esophageal squamous carcinoma cases, andmethylation of RASSF1A gene has been detected in2of100adjacent tissues(2%). The RASSF1A gene promoter was highly methylated in cancer tissues，and there were significant Difference between normal esophagus tissues andesophageal squamous carcinoma (P<0.05). The express of DNMT1protein hasbeen detected in61of100（61%）esophageal squamous carcinoma cases, andnone in adjacent tissues. DNMT1proteins is highly expressed in cancer tissues, and there were significant Difference between normal esophagus tissues andesophageal squamous carcinoma (P<0.05). In the CpG island methylatedesophageal squamous carcinoma cases, the DNMT1protein has been detected in41of45(91%), while in non-methylated cancer cases,20of55(36.3%), and thedifference is significant (P<0.05). The methylation level of RASSF1A and theexpression of DNAMT1protein are not statistically correlated (P>0.05) withother clinicopathological parameters like smoking, gender, age, tumor size,lymphatic metastasis and clinical stages, etc.Conclusions: In tumor adjacent tissues, both of the CpG island methylationof RASSF1A gene promoter and the expression of DNMT1protein aresignificantly low than cancer tissues (P<0.01). The CpG island methylation levelof RASSF1A gene is significantly different (P<0.01)in DNMT1negative andpositive tissues. The CpG island methylation level of RASSF1A gene and theexpression of DNMT1protein were correlated with esophageal squamouscarcinoma tumorigenesis.