DACT2 gene promoter area methylation status and mRNA expression in renal cell carcinoma / 重庆医学

ABSTRACT

Objective To explore the role of the DACT2 gene in the occurrence and development of renal cell carcinoma(RCC).Methods The samples of RCC tissues and corresponding tumor-adjacent tissues after radical operation and normal kidney tissues were collected.The methylation specific PCR (MSP) and real time fluorescence reverse transcriptase-PCR (RT-PCR) methods were adopted to detect the methylation status and mRNA expression of DACT2.The streptavidin-peroxidase (SP) method labeled by immunohistochemistry peroxidase was used to examine the expression of β-catenin protein.Then the relationship between DACT2 gene methylation status and mRNA expression with the clinicopathologic characteristics was analyzed.The relationship between DACT2 gene methylation with mRNA and β-catenin expression was analysed,as well.Results The DACT2 mRNA relative expression level in RCC tissues was 0.427±0.025,which was significantly lower than (0.801±0.047) in tumor-adjacent tissues and (0.872±0.022) in normal tissue,the positive rate of DACT2 gene methylation in RCC tissues was 45.76%,which was significantly higher than 6.78% in tumor-adjacent tissues and 5.08% in normal tissues,the difference was statistically significant (P0.05).The DACT2 gene mRNA expression level in RCC tissues and promoter area methylation occurrence rate had no obvious correlation with the clinical data such as patients age,gender,tumor size,clinical stage and Fuhrman grade (P>0.05).The DACT2 gene mRNA relative level in the methylation group was lower than that in the non-methylation group,the difference was statistically significant (P<0.05).The expression rate of β-catenin protein in cytoplasma in RCC tissues was higher than that in the tumor-adjacent tissues and normal tissues,the difference was statistically significant (P<0.05),moreover,DACT2 gen methylation had a positive correlation with β-catenin protein expression (r=0.324,P=0.012).Conclusion The decrease of DACT2 gene promoter area methylation and mRNA relative expression level may participate in the RCC occurrence,but has no relationship with RCC clinical progression.Methylation occurred in DACT2 gene promoter area may be one of reasons causing mRNA relative expression decrase.DACT2 gene methylation occurrence in RCC tissue might be related to the high expression of β-catenin.