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.
Keywords: DNA methyltransferase; gastrointestinal stromal tumor; methyl-CpG-binding domain protein 2.