Expression of DNMTs and MBD2 in GIST.

The aim of this study was to investigate the protein expression of DNA methyltransferases (DNMTs, including DNMT1, DNMT2, DNMT3A, DNMT3B and DNMT3L) and methyl-CpG-binding domain protein 2 (MBD2) in gastrointestinal stromal tumor (GIST). Immunohistochemistry and western blot analysis were used to detect expression of DNMT and MBD2 in 15 pairs of adult GIST and matched non-tumor tissues. The protein expression of DNMT1, DNMT2, DNMT3B, DNMT3L and MBD2 was significantly higher in adult GISTs compared to the matched non-tumor tissues (P<0.05). However, no significant difference was detected in the protein expression of DNMT3A between tumor and non-tumor tissues (P>0.05). Associations between DNMT1 expression and mitotic index, DNMT3B expression and tumor size, as well as DNMT3L expression and Helicobacter pylori infection were detected in GISTs (P<0.05). In conclusion, GISTs exhibit a high protein expression of DNMT (with the exception of DNMT3A) and MBD2.