Dr. Chris Pelloski presented his analysis of methylation status in glioblastoma at the American Association for Cancer Research "Molecular Diagnostics in Cancer Therapeutic Development" meeting being held at the moment. AACR made a press release that you can see here:

Methylation levels key to glioblastoma survival

Quote:
"This study shows that the methylation status of CpG islands may serve a robust, and previously unexplored, source of biomarkers for this disease," said lead author Christopher E. Pelloski, M.D., an assistant professor of radiation oncology and pathology at M. D. Anderson. "It also indicates that there seems to be a common theme to glioblastoma that the more closely the tumor cells resemble cells of neural development, the less aggressive the clinical course; whereas if they more resemble mesenchymal cells, which are poorly differentiated and invasive, the worse the clinical outcome will be.