Abstract
The present study aimed to investigate the association between the methylation status of the reversion-inducing cysteine-rich protein with kazal motifs (RECK) gene and its mRNA expression levels in patients with esophageal squamous cell carcinoma (ESCC). The methylation status of RECK was analyzed by methylation-specific polymerase chain reaction (PCR), and RECK mRNA expression levels were analyzed by quantitative PCR, in 310 paired ESCC tissues. The mean RECK methylation index (MI) was 0.65 in ESCCs and 0.49 in non-tumor samples. There was a significant association between RECK methylation and the American Joint Committee on Cancer stage and lymph node metastasis in ESCC (P<0.0001; P=0.001). The mRNA expression level of RECK was lower in ESCC tissues (mean(-∆Cq)=-4.66) compared with non-tumor tissues (mean(-∆Cq)=-2.79), and decreased RECK mRNA expression levels were associated with lymph node metastasis in ESCC. In addition, RECK mRNA levels were decreased in ESCC patients with hypermethylation of the RECK gene (∆MI >0.16; mean(-∆∆Cq)=-2.85) compared with those with hypomethylation of the RECK gene (∆MI ≤0.16; mean(-∆∆Ct)=-0.83), and there was a significant difference in the mRNA expression levels of RECK between those with N(0-1) and N(2-3) lymph node metastasis (P<0.0001). A significant correlation was observed between RECK mRNA expression levels, the MI of RECK and poor postoperative survival (P=0.0003; P<0.0001). The results of the present study suggested that promoter hypermethylation may be an important factor for loss of RECK mRNA expression and may be an indicator of poor survival in ESCC.