Hypermethylation of EDNRB promoter contributes to the risk of colorectal cancer

OBJECTIVE: Colorectal cancer (CRC) is one of the most common digestive malignancies in the world. EDNRB is a new candidate tumor suppressor gene which is often down-regulated or even silenced by promoter hypermethylation in various human cancers. However, the function of EDNRB gene in CRC remains unknown. In this study, we examined the expression and DNA methylation of EDNRB in CRC tissues. METHODS: A total of 42 paired CRC and adjacent normal tissue samples were used to determine mRNA levels and DNA methylation status of EDNRB gene by qRT-PCR and methylation-specific PCR (MSP), respectively. RESULTS: Our study showed that EDNRB promoter hypermethylation was more frequently in CRC tissues than in the normal tissues (92.86 versus 59.52, p = 0.001). Consequently, significantly lower level of EDNRB mRNA was found in CRC tumor samples than in normal samples (0.31 ± 0.91 versus 0.70 ± 1.18, p = 0.032). CONCLUSIONS: Our results suggested that EDNRB promoter hypermethylation might downregulate its gene expression in CRC, and thus played an important role in the development of CRC. THE VIRTUAL SLIDE: The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/7420980471113303