Browsing by Author "Olgun, Nur"

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Determination of a New Biomarker at the Level of Gene Alteration in Cisplatin Ototoxicity
(MDPI, 2025) Kizmazoglu, Deniz; Erol, Aylin; Aktas, Tekincan Cagri; Olgun, Yuksel; Demir, Ayse Banu; Altun, Zekiye; Olgun, Nur
Cisplatin is an alkylating chemotherapeutic drug used in the treatment of many pediatric solid tumors, and cisplatin ototoxicity is characterized by sensorineural, bilateral, irreversible, and progressive hearing loss. The aim of this study is to identify biomarkers that may serve as predictors of cisplatin-induced ototoxicity in pediatric cancers. In our preliminary study, patients with severe hearing loss were analyzed using the comparative genomic hybridization (CGH) method. Mutations were identified in the following genes: ADAM6, SIX3, GNAS, NDUFV1, H19, DEFA4, and ZIM2. Based on these data, we aimed to investigate the mutation status of these candidate genes in a larger population of pediatric cancer patients treated with cisplatin. DNA samples were extracted from the mononuclear cells of peripheral blood samples obtained from 82 patients. These genes were analyzed using the RT-PCR technique, and ototoxicity was assessed using the Brock and Muenster classifications. Hearing loss was detected in 28% of patients; 76.8% and 23.2% had mild and severe hearing loss, respectively. A significant correlation was found between ZIM2 gene amplification and the presence of ototoxicity (rho = 0.461, p = 0.003), especially in advanced-stage cancer patients with severe hearing loss (rho = 0.38, p = 0.017). Our findings suggest that ZIM2 is a promising biomarker for predicting cisplatin ototoxicity.
Citation - WoS: 1
Superoxide Dismutase 2 Protein Levels in Blood May Act as a Prognostic Marker for High-Risk Neuroblastoma Patients
(Dokuz Eylul Univ Inst Health Sciences, 2023) Demir, Ayse Banu; Altun, Zekiye; Aktas, Safiye; Olgun, Nur
Purpose: Determination of proteomic differences plays an important role in biomarker investigations. Due to its heterogenic molecular background, identification of certain biomarkers is still a demand both for diagnosis and prognosis of neuroblastoma. In this study, it is aimed to identify marker proteins/mechanisms that may play role in neuroblastoma prognosis. Material and Methods: Real-time PCR analyses were performed for 2p24.3, 11q23, 1p36 and 17q25 status from tumor samples of the patients to determine the risk groups. A proteomic approach was used for different risk groups of the disease by using matrix-assisted laser desorption ionization-time of flight (MALDI-TOF/TOF) approach. Mononuclear cell pools from blood samples of patients for different risk groups were constructed and protein expression changes for different groups were identified. Results: Manganese-superoxide dismutase (SOD2) protein was found to significantly increase in high -risk group of neuroblastoma patients. Conclusion: Our results showed that SOD2 may play an important role in neuroblastoma progression and be a candidate prognostic peripheral blood marker for neuroblastoma patients.