Prognosis of Glioblastoma With Oligodendroglioma Component is Associated With the IDH1 Mutation and MGMT Methylation Status

Jae Kyung Myung; Hwa Jin Cho; Hanna Kim; Chul-Kee Park; Se Hoon Lee; Seung Hong Choi; Peom Park; Jung Min Yoon; Sung-Hye Park

doi:10.1016/j.tranon.2014.10.002

Prognosis of Glioblastoma With Oligodendroglioma Component is Associated With the IDH1 Mutation and MGMT Methylation Status

Transl Oncol. 2014 Dec;7(6):712-9. doi: 10.1016/j.tranon.2014.10.002.

Authors

Jae Kyung Myung¹, Hwa Jin Cho², Hanna Kim², Chul-Kee Park³, Se Hoon Lee⁴, Seung Hong Choi⁵, Peom Park⁶, Jung Min Yoon⁶, Sung-Hye Park⁷

Affiliations

¹ Department of Pathology, Korea Institute of Radiological and Medical Science, Seoul, Republic of Korea.
² Department of Pathology, Seoul National University Hospital, College of Medicine, Seoul, Republic of Korea.
³ Department of Neurosurgery, Seoul National University Hospital, College of Medicine, Seoul, Republic of Korea.
⁴ Department of Internal Medicine, Seoul National University Hospital, College of Medicine, Seoul, Republic of Korea.
⁵ Department of Radiology, Seoul National University Hospital, College of Medicine, Seoul, Republic of Korea.
⁶ Department of Industrial Engineering, Ajou University, Suwon, Republic of Korea.
⁷ Department of Pathology, Seoul National University Hospital, College of Medicine, Seoul, Republic of Korea; Neuroscience Institute, Seoul National University, College of Medicine, Seoul, Republic of Korea. Electronic address: shparknp@snu.ac.kr.

Abstract

Glioblastoma (GBM) with oligodendroglioma component (GBMO) is a newly described GBM subtype in the 2007 World Health Organization classification. However, its biological and genetic characteristics are largely unknown. We investigated the clinicopathological and molecular features of 34 GBMOs and compared the survival rate of these patients with those of patients with astrocytoma, oligodendroglioma, anaplastic oligoastrocytoma (AOA), and conventional GBMs in our hospital. GBMO could be divided into two groups based on the presence of an IDH1 mutation. The IDH1 mutation was more frequently found in secondary GBMO, which had lower frequencies of EGFR amplification but higher MGMT methylation than the wild type IDH1 group, and patients with mutant IDH1 GBMO were on average younger than those with wild-type IDH1. Therefore, GBMO is a clinically and molecularly heterogeneous subtype, largely belonging to a proneural and classical subtype of GBM. The survival rate of GBMO patients itself was worse than that of AOA patients but not significantly better than that of conventional GBM patients. GBMO survival was independent of the dominant histopathological subtype i.e., astrocyte-dominant or oligodendroglioma -dominant, but it was significantly associated with the IDH1 mutation and MGMT methylation status. Therefore, GBMO should be regarded as a separate entity from AOA and must be classified as a subtype of GBM. However, further study is needed to determine whether it is a pathologic variant or a pattern of GBM because GBMO has a similar prognosis to conventional GBMs.