To further examine CRE methylation in different cis-acting elements of GDNF promoter II in GBM tissue and cells, DNA methylation of CRE in silencer II and enhancer II of GDNF promoter II was quantitatively assessed in GBM and NB tissues, as well as in U251, U343, and NHA cells. The gene discussed is GDNF; the disease is neuroblastoma.