Correlation between MBD2 Expressions in Colorectal Cancer Tissue and Blood

Park, Hyun Koun; Lee, Jeong Eun; Lee, Ryung Ah; Kim, Kwang Ho

Abstract

PURPOSE: DNA methylation is a major epigenetic mechanism for modification of genetic expression without a change in the DNA sequence. MBD2 (methyl-CpG-binding domain 2 protein) belongs to a family of enzymes concerning of DNA demethylation and suppresses the hypermethylation of the CpG island and DNA transcription. In this study, we investigated the change of MBD2 expression in the blood and tissue of colorectal cancer patients and compared the two expression levels.
METHODS
The 68 patients included in this study were patients with colorectal cancer who had undergone surgery at our hospital, and 50 other patients with no malignant disease were recruited from normal populations. Total RNA samples were isolated from whole blood samples and cancer tissues of specimens using a TRI REAGENT BD kit. MBD 2 expression was measured by real-time quantitative reverse transcription-polymerase chain reaction assays.
RESULTS
The mean age was older in the case group than in the control group. The mean expression level of MBD2 in blood was not different between the two groups. In the case group, the tissue MBD2 expression was lower than the blood MBD2 expression under all conditions, and that difference was statistically significant (P<0.01). The expression of MBD2 in cancer tissue showed a negative correlation with that in the blood of cancer patients, correlation coefficient of R=0.073, but that result was not statistically significant (P=0.611).
CONCLUSIONS
The blood MBD2 expression was statistically the same in the cancer and the control groups. In the cancer group, blood MBD2 expression was significantly higher than tissue MBD2 expression. The reverse correlation between blood MBD2 expression and tissue MBD2 expression in cancer patients suggests that MBD2 may affect the mechanism of carcinogenesis.