Frontal glioblastoma multiforme may be biologically distinct from non-frontal and multilobar tumors.
Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults and carries a grim prognosis. Lobar GBM, notably those localized to the frontal lobe, are generally more amenable to complete surgical resection, and may carry a better prognosis. The biology of differently localized GBM has been reported scarcely in terms of prognostic markers, including isocitrate dehydrogenase 1 (IDH1) mutation and O(6)-methylguanine-methyltransferase (MGMT) methylation. To our knowledge, there has been no evaluation in the literature of different proliferation indexes in different GBM locations in the brain. We performed a retrospective evaluation of our prospectively collected database to assess the rate of IDH1 positivity, MGMT methylation and Ki67 index for GBM located in the frontal lobes alone, lobar GBM in other supra-tentorial lobes and multilobar GBM. IDH1 mutated tumors were localized in the frontal lobes in 50.0%, whereas only 20.3% of IDH1 wild-type tumors were localized in the frontal lobe (p=0.006); MGMT methylated tumors were localized in the frontal lobe in 32.0% of the cases. Only 13.75% of the MGMT unmethylated tumors were localized to the frontal lobe (p=0.005); Tumors with higher Ki67 proliferation index were more likely to be localized in the frontal lobe (40.6% vs. 19.5%, p=0.019). This is the largest cohort of GBM assessed for these purposes in the literature. Frontal lobe GBMs may be intrinsically biologically distinct from GBM in other lobes and from multilobar tumors.
Department of Neurosurgery, The Royal Melbourne Hospital, 300 Grattan Street, Parkville, VIC 3052, Australia. Electronic address: iddo.paldor@mh.org.au.
Iddo
I
Paldor
Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia.
Fiona C
FC
Pearce
Department of Neurosurgery, The Royal Melbourne Hospital, 300 Grattan Street, Parkville, VIC 3052, Australia; Department of Surgery, University of Melbourne, Parkville, VIC, Australia.
Katharine J
KJ
Drummond
Department of Neurosurgery, The Royal Melbourne Hospital, 300 Grattan Street, Parkville, VIC 3052, Australia; Department of Surgery, University of Melbourne, Parkville, VIC, Australia.
Andrew H
AH
Kaye
D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D005260:Female; D005625:Frontal Lobe / Q000473:pathology*; D005909:Glioblastoma / Q000175:diagnosis* / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007521:Isocitrate Dehydrogenase / Q000235:genetics; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D008745:Methylation; D008875:Middle Aged; D009154:Mutation; D019853:O(6)-Methylguanine-DNA Methyltransferase / Q000378:metabolism; D011379:Prognosis; D012189:Retrospective Studies
D019394:Ki-67 Antigen; D007521:Isocitrate Dehydrogenase; D019853:O(6)-Methylguanine-DNA Methyltransferase
Glioblastoma; IDH-1 mutation; Ki-67 proliferation index; MGMT methylation; Tumor location