Unexpectedly, the overwhelm ing vast majority within the tumors studied were unmethylated. Upon examination on the GBMs that did present some degree of methylation, no hotspots of methylation had been identified. Sequencing and MSP PCR didn’t concur in 20% from the cases. On closer examination of the sequence, the four CG areas targeted through the MSP PCR primers had been not methylated, but CGs had been methylated elsewhere. This highlights the really need to sequence large sec tions in the promoter when examining methylation standing. Final results at the mRNA and protein expression amounts will shed light on this. PA 24. PTEN Loss Is a Superior INDICATOR OF SURVIVAL THAN HISTOLOGIC GRADE IN CONSENSUS GRADE 2 AND three ASTROCYTOMAS A. Misra,1 I. Smirnov,1 S. VandenBerg,one M. Ware,1 C. Hong,one Y. Hirose,two E. Mirvish,one L. Kapp,one S. Kharbanda,3 J. Nigro,one E. Pan,4 L. Prestegarden,1 R. Yeh,one J. Costello,1 A. Yates,5 D. Pearl,five B. Scheithauer,6 P.
Burger,seven C. Giannini,6 H. Phillips,three K. Aldape,8 and B. G. Feuerstein1, Pim cancer 1Univ. of California, San Francisco, CA, USA, 2Keio University School of Medicine, Tokyo, Japan, 3Genentech Inc. South San Francisco, CA, USA, 4Florida Hospital Cancer Institute, Orlando, FL, USA, 5Ohio State University, OH, USA, 6Mayo Clinic, Rochester, MN, USA, 7Johns Hopkins Health-related Center, Baltimore, MD, USA, 8The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA Pathologic grade predicts outcome in astrocytic tumors. WHO grading is according to cellular atypia, mitotic action, endothelial proliferation, and necrosis. Grade 2 tumors ordinarily have cellular atypia, whereas grade three tumors often have both atypia and mitotic action. On the other hand, some sufferers with grade 2 and three tumors have bad survival, and many others have really good survival. There isn’t a regarded marker to detect the atypical survivors.
We employed TW37 DNA microarrays to examine 21 consensus grade 2 and 41 consensus grade 3 astro cytomas. Consensus was defined as diagnostic agreement between no less than four of 6 neuropathologists. We implemented Pearsons correlation analyses to identify highly correlated chromosomal aberrations, cluster examination to iden tify genetic groups, significance examination of microarrays to determine genetic variations between grades, and also the Cox proportional hazards model to determine genetic markers linked with survival. Our preliminary analyses propose that main interchromosomal correlations for copy amount loss and get come about in grade two tumors in between chromosome four and chrs 7, 9, 14, and 17, chr seven and chrs 9, 14, and 17, and chrs 1 and X, and in grade 3 tumors in between chrs 1 and six, chrs 4 and 7/8, chrs 6 and 16/17, chrs 7 and 10, and chrs 9 and 15. Our findings also propose that losses on chr ten encompass the PTEN gene and that the chr 13 loss includes a 5 Mb area at 13q22.