Post-hoc analysis revealed that the promoter region of SFRP4 gene in diffuse astrocytomas was significantly more frequently methylated than in glioblastomas (p < 0.001), consistently glioblastomas had a significantly higher number of unmethylated promoters compared to diffuse astrocytomas (p < 0.001). The gene discussed is SFRP4; the disease is diffuse astrocytoma.