Browsing by Author "Ruksen, Mete"

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Citation - WoS: 10
Citation - Scopus: 11
Minimally Invasive Detection of Idh1 Mutation With Cell-Free Circulating Tumor Dna and D-2 D/L-2-hydroxyglutarate Ratio in Gliomas
(Oxford Univ Press Inc, 2022) Tuna, Gamze; Dal-Bekar, Nazli Ecem; Akay, Ali; Ruksen, Mete; Islekel, Sertac; Islekel, Gul Huray
Isocitrate dehydrogenase-1 (IDH1) mutation is accepted as one of the earliest events in tumorigenesis in gliomas. This mutation causes preferential accumulation of D- relative to L-enantiomer of 2-hydroxyglutarate (2-HG). Minimally invasive techniques to detect IDH1 mutation may prove useful for clinical practice. We adopted 2 different diagnostic approaches to detect IDH1 mutation status in glioma patients: Evaluation of D- and L-2-HG levels in cerebrospinal fluid (CSF), urine, and plasma, and identification of IDH1 mutation using cell-free circulating tumor DNA (ctDNA) in CSF and plasma. Forty-nine glioma patients in different stages were included. Levels of D- and L-2-HG were determined using liquid chromatography-tandem mass spectrometry; IDH1 R132H mutation was determined by digital-PCR. D-2-HG levels and D/L-2-HG ratio (rDL) in CSF and rDL in plasma were significantly higher in the mutant group than in the wild-type group (p = 0.029, 0.032, 0.001, respectively). The IDH1 mutation detection rates in CSF- and plasma-ctDNA were 63.2% and 25.0%, respectively. These data indicate that D-2-HG values in CSF and rDL in plasma and CSF can be considered as significant contributors to the identification of IDH1 mutation status. In addition, detection of IDH1 mutation in CSF-ctDNA from glioma patients provides a basis for future use of ctDNA for minimally invasive clinical assessment of gliomas.
Stereotactic Radiosurgery-Induced Peritumoral Edema in Asymptomatic Convexity, Parasagittal, and Parafalcine Meningiomas
(Turkish Neurosurgical Soc, 2026) Can, Osman Burak; Ruksen, Mete; Isman, Burcu Durmak; Askeroglu, Mehmet Orbay; Zorlu, Seray; Yuksel, Alper; Akay, Ali; Durmak Isman, Burcu
AIM: To evaluate the incidence and identify the risk factors of stereotactic radiosurgery (SRS)-induced peritumoral edema (PTE) in the asymptomatic convexity, parasagittal, and parafalcine meningiomas without pre-existing PTE. MATERIAL and METHODS: We retrospectively analyzed 52 patients with asymptomatic convexity, parasagittal, or parafalcine meningiomas without pre-existing PTE who underwent single-fraction Gamma Knife radiosurgery between 2019 and 2024. The median tumor volume and the maximum tumor diameter were 3.3 cc (range: 0.31-10.2 cc) and 2.0 cm (range: 0.98-3.1 cm), respectively. The median margin dose was 12 Gy (range: 11 Gy-13 Gy). The median radiological and clinical follow-up durations were 21 months (range: 6-65 months) and 26 months (range: 12-66 months), respectively. RESULTS: SRS-induced PTE occurred in 5.8% of patients (n=3), exclusively in elderly individuals (>= 65 years) with parasagittal or parafalcine meningiomas. No cases were observed in convexity meningiomas (0/24). Multivariable analysis revealed a trend toward statistical significance for the association between age and SRS-induced PTE (p=0.074). In the overall cohort, the incidence of SRS-induced PTE was significantly higher in elderly patients compared to younger patients (<65 years) (3/14 vs. 0/38, p=0.016), and this difference remained significant within the parasagittal/parafalcine subgroup (3/7 vs. 0/21, p=0.011).
CONCLUSION: SRS appears to be a safe treatment modality in terms of PTE risk in patients aged below 65 years with asymptomatic convexity, parasagittal, or parafalcine meningiomas without pre-existing PTE. In contrast, elderly patients with parasagittal or parafalcine meningiomas may be more susceptible to SRS-induced PTE, thereby warranting a more cautious approach to SRS in this subgroup. Additional studies involving larger cohorts are warranted to validate these findings.