Abstract:

Objective To research the effect of the Kiss-1 gene promoter methylation on the Kiss-1 gene expression in colorectal carcinoma tissue,and to analyze
 the relationship between the Kiss-1 gene methylation and the clinical pathological features of colorectal carcinoma and its clinical significance.
Methods The Kiss-1 gene promotor region methylation,Kiss-1 gene mRNA and protein expressions  were detected respectively by methylation-specific PCR,Real-time PCR and Western blotting method in 126 cases of colorectal carcinoma tissue and para-cacinoma  normal  colorectal tissue.Results The positive rate of Kiss-1 gene methylation in colorectal carcinoma tissue (83.33%) was significantly higher than that in normal tissue (30.16%) (P<0.05).In the cancer tissue,the expression levels of Kiss-1 gene mRNA and protein in Kiss-1 gene promoter methylation positive group was lower than
 that in Kiss-1 gene promoter methylation negative group (P<0.05).The positive rate of Kiss-1 gene promoter methylation in T3+T4 stage group was higher than that in T1+T2 stage group (P<0.05),but the Kiss-1 gene mRNA and protein expression levels were lower than those in T1+T2 stage group (P<0.05).In the poorly and moderately differentiated group,the positive rate of Kiss-1 gene promoter methylation was higher than that in well differentiated group (P<0.05),but the mRNA expression level of Kiss-1 gene was lower than that  in well differentiated group (P<0.05).In lymph node metastasis
 group,the positive rate of Kiss-1 gene promoter methylation was higher than that in lymph node negative group (P<0.05),but the mRNA and protein expression levels were lower than those in lymph node negative group (P<0.05). And the positive rate of Kiss-1 gene promoter methylation in distant metastasis group was higher than that in non-distant metastasis group (P<0.05),but the mRNA and protein expressions levels  were lower than those in non-distant metastasis group (P<0.05).There were no significant associations between the positive rate of Kiss-1 gene promoter methylation and the  gender,age,tumor location,and tumor diameter of the patients (P>0.05).Conclusion The Kiss-1 gene promoter methylation in colorectal carcinoma  tissue is associated with the Kiss-1 gene expression level and the malignant characteristics of colorectal carcinoma;Kiss-1 gene promoter methylation may be used as a reference indicator for predicting the risk of metastasis  of colorectal carcinoma.
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Key words: colorectal neoplasms, Kiss-1 gene, DNA methylation, metastasis