AUTHOR=Kurdi Maher , Shafique Butt Nadeem , Baeesa Saleh , Alghamdi Badrah , Maghrabi Yazid , Bardeesi Anas , Saeedi Rothaina , Al-Sinani Taghreed , Alghanmi Najla , Bari Mohammed O., Samkari Alaa , Lary Ahmed I.

TITLE=The Impact of IDH1 Mutation and MGMT Promoter Methylation on Recurrence-Free Interval in Glioblastoma Patients Treated With Radiotherapy and Chemotherapeutic Agents

JOURNAL=Pathology and Oncology Research

VOLUME=27

YEAR=2021

URL=https://www.por-journal.com/journals/pathology-and-oncology-research/articles/10.3389/pore.2021.1609778

DOI=10.3389/pore.2021.1609778

ISSN=1532-2807

ABSTRACT=<p>The aim of this study is to investigate the relationship between isocitrate dehydrogenase-1 (<italic>IDH1</italic>) mutation and O<sup>6</sup>-methylguanine-DNA methyltransferase (<italic>MGMT</italic>) promoter methylation with recurrence-free interval in glioblastoma patients treated with chemoradiotherapies. Clinical data were collected from 82 patients with totally resected glioblastoma and treated with adjuvant therapies from 2014 to 2019. <italic>IDH1</italic> mutation was assessed by immunohistochemistry and <italic>MGMT</italic> promoter methylation was assessed by different sequencing methods. <italic>IDH1</italic> mutation was present in 32 cases and 50 cases were <italic>IDH1</italic> wildtype; 54 and 28 patients had unmethylated and methylated <italic>MGMT</italic> promoter, respectively, Of the 82 patients, 62 patients received chemoradiotherapy while 20 patients only received radiation. Approximately, 61% of patients had a tumor recurrence after 1 year, and 39% showed a recurrence before 1 year of treatment. There was no significant relationship between <italic>IDH1</italic> mutation and <italic>MGMT</italic> promoter methylation (<italic>p</italic>-value = 0.972). Patients with <italic>IDH1</italic> mutation and their age &lt;50 years showed a significant difference in recurrence-free interval (<italic>p</italic>-value = 0.014). Difference in recurrence-free interval was also statistically observed in patients with unmethylated <italic>MGMT</italic> promoter and treated with chemoradiotherapies (<italic>p</italic>-value = 0.031), by which they showed a late tumor recurrence (<italic>p</italic>-value = 0.016). This revealed that <italic>IDH1</italic> mutation and <italic>MGMT</italic> methylation are independent prognostic factors in glioblastoma. Although <italic>IDH1</italic>-mutant glioblastomas showed late tumor recurrence in patients less than 50 years old, the type of treatment modalities may not show additional beneficial outcome. Patients with unmethylated <italic>MGMT</italic> and <italic>IDH1</italic> mutation, treated with different chemoradiotherapies, showed a late tumor recurrence.</p>