title: Correlation among pathology, genetic and epigenetic profiles, and clinical outcome in oligodendroglial tumors.
abstract: Recent studies have revealed a correlation between specific genetic changes, such as loss of chromosome 1p and 19q, and sensitivity of oligodendroglial neoplasm to radiotherapy and chemotherapy; epigenetic changes also play an important role in some tumors. In this retrospective study, we analyzed chromosomal alterations in 17 loci and promoter methylation status of 8 tumor-related genes in 49 oligodendroglial tumors (29 WHO grade II and 11 WHO grade III oligodendrogliomas; 7 WHO grade II and 2 WHO grade III oligoastrocytomas) using quantitative microsatellite analysis and methylation-specific polymerase chain reaction and correlated this information with clinical data. We also performed immunohistochemical stains for Ki-67 and O (6)-methyl guanine-DNA methyl transferase. Our results showed that the frequency of deletions in regions on 1p, 9p, 10q, 17p and 19q were 71.4%, 26.5%, 6.1%, 69.4% and 89.8%, respectively. Promoter methylation was detected in p14, p15, p16, p53, p73, PTEN, MGMT and RASSF1A genes in 24.5%, 6.1%, 46.9%, 0%, 6.1%, 42.9%, 53.1% and 77.6% of tumors, respectively. Statistical analysis identified that 9p22 loss, p73 methylation and p15 methylation were independently associated with reduced overall survival, and Ki-67 labeling index (LI) > or = 5%, 9p22 loss, no loss of 19q, p73 methylation, p14 methylation and unmethylated MGMT predicted shorter progression-free survival. Our findings suggest that the frequent deletion and hypermethylation of tumor-related genes may represent a mechanism of tumor development and progression and emphasize the importance of defining new molecular markers for predicting prognosis, tumor recurrence and therapeutic response in cancer management.
authors.affiliation: Division of Neurosurgery, Department of Surgery, National Taiwan University Hospital, Yun-Lin Branch, Yun-Lin County, [corrected] Taiwan.
authors.forename: Lu-Ting
authors.initials: LT
authors.lastname: Kuo
authors.forename: Kuang-Ting
authors.initials: KT
authors.lastname: Kuo
authors.forename: Ming-Jang
authors.initials: MJ
authors.lastname: Lee
authors.forename: Chih-Chun
authors.initials: CC
authors.lastname: Wei
authors.forename: Francesco
authors.initials: F
authors.lastname: Scaravilli
authors.forename: Jui-Chang
authors.initials: JC
authors.lastname: Tsai
authors.forename: Ham-Min
authors.initials: HM
authors.lastname: Tseng
authors.forename: Meng-Fai
authors.initials: MF
authors.lastname: Kuo
authors.forename: Yong-Kwang
authors.initials: YK
authors.lastname: Tu