TY - JOUR
T1 - Somatic mutations in glioblastoma are associated with methylguanine-DNA methyltransferase methylation
AU - Mcdonald, K.L.
AU - Tabone, Tania
AU - Nowak, Anna
AU - Erber, Wendy
PY - 2015
Y1 - 2015
N2 - © 2015, Spandidos Publications. All rights reserved. The high level of methylguanine‑DNA methyltransferase (MGMT) in glioblastoma is responsible for resistance to alkylating agents, such as temozolomide (TMZ). In glioblastomas with a methylated MGMT promoter, MGMT deficiency is presumed, resulting in an enhanced effect of TMZ. The aim of the present study was to investigate whether genomic alterations work synergistically with MGMT methylation status and contribute to the response to treatment and overall prognosis in glioblastoma. The current study included a cohort of 35 glioblastoma patients, with MGMT promoter methylation present in 48% of tumors. MGMT methylation was associated with significantly longer median survival (29.0 months) compared with patients without MGMT methylated tumors (12.0 months), as well as longer median time to progression following TMZ treatment (13.2 months, compared with 5.6 months for patients with an unmethylated MGMT status). In addition, somatic variants in hot spot exonic regions of 50 key cancer genes were examined in these glioblastomas. Non‑synonymous mutations in methylated MGMT glioblastomas were four times higher compared with unmethylated MGMT glioblastomas. Furthermore, significantly increased frequencies of mutations in the TP53, CDKN2A, PTEN and PIK3CA genes were detected in MGMT methylated glioblastomas. The relative significance of these mutations, and their contribution to TMZ sensitivity, adjunct to MGMT methylation, require further investigation in a larger cohort.
AB - © 2015, Spandidos Publications. All rights reserved. The high level of methylguanine‑DNA methyltransferase (MGMT) in glioblastoma is responsible for resistance to alkylating agents, such as temozolomide (TMZ). In glioblastomas with a methylated MGMT promoter, MGMT deficiency is presumed, resulting in an enhanced effect of TMZ. The aim of the present study was to investigate whether genomic alterations work synergistically with MGMT methylation status and contribute to the response to treatment and overall prognosis in glioblastoma. The current study included a cohort of 35 glioblastoma patients, with MGMT promoter methylation present in 48% of tumors. MGMT methylation was associated with significantly longer median survival (29.0 months) compared with patients without MGMT methylated tumors (12.0 months), as well as longer median time to progression following TMZ treatment (13.2 months, compared with 5.6 months for patients with an unmethylated MGMT status). In addition, somatic variants in hot spot exonic regions of 50 key cancer genes were examined in these glioblastomas. Non‑synonymous mutations in methylated MGMT glioblastomas were four times higher compared with unmethylated MGMT glioblastomas. Furthermore, significantly increased frequencies of mutations in the TP53, CDKN2A, PTEN and PIK3CA genes were detected in MGMT methylated glioblastomas. The relative significance of these mutations, and their contribution to TMZ sensitivity, adjunct to MGMT methylation, require further investigation in a larger cohort.
U2 - 10.3892/ol.2015.2980
DO - 10.3892/ol.2015.2980
M3 - Article
C2 - 26137013
VL - 9
SP - 2063
EP - 2067
JO - Oncology Letters
JF - Oncology Letters
SN - 1792-1074
IS - 5
ER -