A total of 124 of 160 glioma samples (77.5%) displayed CpG island hypermethylation of both p73, p21 genes associated with the loss of mRNA expression (P < 0.001) and the loss of protein expressions (p53 independent p21 expression). p73 gene showed increased methylation frequency in all grades, 40 of 60 (66%) glioblastomas and 16 of 30 (53.3%) anaplastic astrocytoma, 10 of 20(50%) oligodendrogliomas, 8 of 20 (40%) ependymoma, and low-grade glioma 6 of 20 (30%).
Using PCR-SSCP and gene sequencing, we analyzed the TP53 and TP73 genes in a case of a grade III anaplastic astrocytoma that progressed to glioblastoma.