Methylation status of promoter 1 region of GDNF gene in human glioma cells.

OBJECTIVE This study aimed to investigate the methylation status of promoter 1 region of glial cell line-derived neurotrophic factor (GDNF) in human glioma cells and to explore the effect of GDNF methylation on the expression of GDNF in glioma. METHODS GDNF gene mutation was detected by sequencing in 10 patients with glioma and 5 healthy controls. Bisulfite modification for analysis of DNA methylation was done to detect the methylation status of promoter 1 region of GDNF in 20 patients with glioma (10 with poorly differentiated and 10 with well differentiated) and 5 healthy controls. RESULTS There was no mutation at the promoter 1 region of GDNF gene in glioma. The incidence of methylation of GDNF gene at the promoter 1 region in healthy control, patients with poorly differentiated glioma and those with well differentiated glioma was 72.25%, 86.25% and 86.75%. The incidence of GDNF methylation in glioma was significantly higher than that in the normal brain (P<0.05); while there was no significant difference between well differentiated glioma and poorly differentiated glioma. CONCLUSIONS Hypermethylation occurs in the promoter 1 region of GDNF and may influence the expression of GDNF in glioma.