Methylation Status Of MAL And HIN-1Gene In Esophageal Squamous Cell Carcinoma

BackgroundEsophageal cancer is a common malignant tumor with high incidence and mortality. Our coutry is a high-incidence area of esophageal cancer. Squamous cacinoma is the main kind of esophageal cancer,while adenocacinoma is rare.The early simptoms of esophageal cancer are not very typical,so the cases are often in advanced stage with poor prognosis when diagnosed.Therefore,early diagnosis and treatment are crucial.DNA methylation is an important genetics mechanism in tumorigenesis. DNA methylation can make gene inactivation without changing gene sequences. In recent years,many genes are found inactivation with DNA methylation in esophageal cancer.MAL gene is located on human chromosome2q13, widely expressed in many kinds of cells. MAL gene plays an important role in maintaining the normal function of cells.HIN-1gene is located on human chomosome5q35, which expresses a kind of secreted globulin that can reglulate the cell growth.Studies have shown that MAL and HIN-1genes are down-regulated in a variety of tumours,which are candidate tumor suppressor genes.DNA methylation may be the main mechanism of inactivation of these two genes.Therefore,we study the methylation status of MAL and HIN-1genes in esopheal squamous cell cacinoma to explore the relationship between these two genes and the occurrence and development of esopheal cancer,in order to provide some reference value for the diagnosis and treatment of esopheal cancer.ObjectionTo study the methylation status of MAL and HIN-1genes in esopheal squamous cell cacinoma and explore the relationship between these two genes and the occurrence and development of esopheal squamous cell cacinoma.MethodsIn this experiment,35cases of esophageal squamous cell cacinoma pathological specimens were collected from the first affiliated hospital of zhengzhou university from2009to2010.Methylation-specific PCR was used to detect the methylation status of MAL and HIN-1gene in esophageal cancer and para-cancerous tissues.The data were analyzed by chi-squared test and Fisher’s exact test.Results1.The methylation rate of MAL gene in esophageal squamous cell carcinoma is74.29%. The methylation rate of MAL gene in para-cancerous tissues is5.71%. The difference of methylation incidence of MAL gene between esophageal cancer and para-cancerous tissues was statistically significant (X2=31.49，P<0.05).The methylation status of MAL gene in esophageal squamous cell carcinoma is not related to tumor size, depth of invasion, differentiation degree, lymphnode metastasis (P>0.05)2. The methylation rate of HIN-1gene in esophageal squamous cell carcinoma is62.86%. The methylation rate of HIN-1gene in para-cancerous tissues is8.57%. The difference of methylation incidence of HIN-1gene between esophageal cancer and para-cancerous tissues was statistically significant (X2=20.16, P<0.05).The methylation status of HIN-1gene in esophageal squamous cell carcinoma is not related to tumor size, depth of invasion, differentiation degree, lymphnode metastasis (P>0.05)3. The difference of total methylation incidence of MAL and HIN-1gene between esophageal cancer and para-cancerous tissues was statistically significant (X2=33.02, P<0.05).There was no significant correlation on methylation incidence between MAL and HIN-1gene in esophageal cancer (P<0.05)Conclusions1. DNA methylation may be one of the possible mechanisms which reduce down regulating expression of MAL and HIN-1gene in esophageal squamous cell cacinoma.2. The methylation rate of MAL gene was positive correlated with the methylation rate of HIN-1gene in esophageal squamous cell cacinoma.It suggested that MAL and HIN-1gene may have synergy effect on the genesis of esophageal squamous cell cacinoma.