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Dive into the research topics where Sibel Kahraman Cetintas is active.

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Featured researches published by Sibel Kahraman Cetintas.


Food and Chemical Toxicology | 2013

Radioprotection by two phenolic compounds: Chlorogenic and quinic acid, on X-ray induced DNA damage in human blood lymphocytes in vitro

Nilufer Cinkilic; Sibel Kahraman Cetintas; Tolga Zorlu; Ozgur Vatan; Dilek Yılmaz; Tolga Çavaş; Sema Tunç; Lutfi Ozkan

The present study was designed to determine the radioprotective effect of two phytochemicals, namely, quinic acid and chlorogenic acid, against X-ray irradiation-induced genomic instability in non-tumorigenic human blood lymphocytes. The protective ability of two phenolic acids against radiation-induced DNA damage was assessed using the alkaline comet assay in human blood lymphocytes isolated from two healthy human donors. A Siemens Mevatron MD2 (Siemens AG, USA, 1994) linear accelerator was used for irradiation. The results of the alkaline comet assay revealed that quinic acid and chlorogenic acid decreased the DNA damage induced by X-ray irradiation and provided a significant radioprotective effect. Quinic acid decreased the presence of irradiation-induced DNA damage by 5.99-53.57% and chlorogenic acid by 4.49-48.15%, as determined by the alkaline comet assay. The results show that quinic acid and chlorogenic acid may act as radioprotective compounds. Future studies should focus on determining the mechanism by which these phenolic acids provide radioprotection.


Tumori | 2006

Factors influencing axillary node metastasis in breast cancer.

Sibel Kahraman Cetintas; Meral Kurt; Lutfi Ozkan; K. Engin; Sehsuvar Gokgoz; Ismet Tasdelen

Aims and Background The status of the axillary lymph nodes at the time of diagnosis has been accepted as one of the most important prognostic factors for the overall and disease-free survival of patients with breast cancer. The aim of our study was to determine which factors influence axillary node involvement in invasive breast cancer. Methods The data presented here were obtained from 344 patients who were treated for invasive breast cancer at the Department of Radiation Oncology, Uludag University Medical College, Bursa, Turkey. Possible prognostic factors were categorized as patient related and tumor related. The Mann-Whitney U test was used for univariate analysis and logistic regression was used for multivariate analysis. Results In univariate analysis, a familial cancer history (P = 0.0042), age <40 years (P = 0.0276), higher T stage (P <0.0000), nipple involvement (P = 0.0345), skin involvement (P = 0.0270), perineural invasion (P = 0.0231), and lymphatic vessel invasion (P <0.0000) were correlated with increased axillary node involvement. A higher incidence of ≥4 involved lymph nodes was associated with higher T stage (P = 0.0004), nipple involvement (P = 0.0292), presence of an extensive intraductal component (P = 0.0023), skin involvement (P = 0.0008), perineural invasion (P = 0.0523), and lymphatic vessel invasion (P <0.0000) in univariate analysis. In multivariate analysis, age <40 years (P = 0.0454), cancer history within the family (P = 0.0024), higher T stage (P = 0.0339), lymphatic vessel invasion (P = 0.0003), and perineural invasion (P = 0.0408) were found to be independent factors for axillary lymph node positivity. Age <40 years (P = 0.0221), perineural invasion (P = 0.0408), and an extensive intraductal component (P = 0.0132) were associated with an increased incidence of ≥4 involved nodes in the logistic regression analysis. In patients with breast cancer, the incidence of axillary lymph node involvement was independently influenced by age <40 years, presence of cancer history within the family, higher T stage, lymphatic vessel invasion, and perineural invasion. Conclusions In conclusion, absence of familial cancer history, presence of lymphatic vessel invasion, higher T stage, and age below 40 years independently increased the risk of axillary node involvement. Presence of perineural invasion and lymphatic vessel invasion, age below 40, and an extensive intraductal component of more than 25% independently affected the risk of having ≥4 nodes involved. Patients characterized by these factors may be classified into a higher risk group for nodal involvement, but more data are needed to define factors that can help in the decision-making regarding the omission of axillary treatment.


Tumori | 2012

CK19, CK20, EGFR and HER2 status of circulating tumor cells in patients with breast cancer.

Berrin Tunca; Unal Egeli; Gulsah Cecener; Gulcin Tezcan; Sehsuvar Gokgoz; Ismet Tasdelen; Nuran Bayram; Sahsine Tolunay; Gorkem Umut; Elif Demirdogen; Elif Erturk; Secil Ak; Sibel Kahraman Cetintas; Turkkan Evrensel

AIMS AND BACKGROUND The major cause of death in breast cancer patients is metastasis. Various biomarkers have been used for the early detection of circulating tumor cells in the peripheral blood of breast cancer patients. The aims of the current study were to analyze circulating tumor cells in the blood of breast cancer patients by investigating EGFR, CK19, CK20 and HER2 expression profiles and to evaluate their prognostic importance. METHODS CK19, CK20 and EGFR gene expression profiles were evaluated in the blood samples of 84 female patients with primary invasive ductal breast cancer and 20 healthy female volunteers using SYBR green-based real-time qPCR assays. HER2 expression analyses were conducted in 46 patients who had an HER2-positive primary tumor and in 30 healthy women to determine the cutoff level of positivity. RESULTS The positive rates of CK20, EGFR, CK19 and HER2 mRNA expression in the peripheral blood were 28.57% (24/84), 20.23% (17/84), 5.95% (5/84) and 2.17% (1/46), respectively. The high positive ratio of CK20 mRNA expression in the peripheral blood of breast cancer was identified for the first time in the current study. Significant differences were identified in CK20 expression status and several clinical parameters related with aggressiveness of tumors using a binary logistic regression analysis. Higher CK20-positive levels were observed in patients who had lymph node metastasis and advanced-grade primary tumors, which were estrogen receptor-negative. We have demonstrated that CK20 may be a novel biomarker that is useful to identify circulating tumor cells and predict breast cancer progression. CONCLUSIONS The results suggest that the investigation of CK20 mRNA with other biomarkers in the peripheral blood of breast cancer patients may be useful to monitor the presence of disseminated tumor cells in the blood circulation and to predict the prognosis of breast cancer.


Mutation Research-genetic Toxicology and Environmental Mutagenesis | 2014

Radio-protective effect of cinnamic acid, a phenolic phytochemical, on genomic instability induced by X-rays in human blood lymphocytes in vitro.

Nilufer Cinkilic; Ece Tüzün; Sibel Kahraman Cetintas; Ozgur Vatan; Dilek Yılmaz; Tolga Çavaş; Sema Tunç; Lutfi Ozkan

The present study was designed to determine the protective activity of cinnamic acid against induction by X-rays of genomic instability in normal human blood lymphocytes. This radio-protective activity was assessed by use of the cytokinesis-block micronucleus test and the alkaline comet assay, with human blood lymphocytes isolated from two healthy donors. A Siemens Mevatron MD2 (Siemens AG, USA, 1994) linear accelerator was used for the irradiation with 1 or 2 Gy. Treatment of the lymphocytes with cinnamic acid prior to irradiation reduced the number of micronuclei when compared with that in control samples. Treatment with cinnamic acid without irradiation did not increase the number of micronuclei and did not show a cytostatic effect in the lymphocytes. The results of the alkaline comet assay revealed that cinnamic acid reduces the DNA damage induced by X-rays, showing a significant radio-protective effect. Cinnamic acid decreased the frequency of irradiation-induced micronuclei by 16-55% and reduced DNA breakage by 17-50%, as determined by the alkaline comet assay. Cinnamic acid may thus act as a radio-protective compound, and future studies may focus on elucidating the mechanism by which cinnamic acid offers radioprotection.


Tumori | 2013

The evaluation of bcl-2 expression as a prognostic marker in early stage laryngeal cancer.

Umit Gurlek; Candan Demiröz Abakay; Lutfi Ozkan; Ozlem Saraydaroglu; Meral Kurt; Sibel Kahraman Cetintas

AIMS AND BACKGROUND To evaluate the effect of bcl-2 expression on the local control and overall survival of patients with early stage laryngeal cancer treated with radiotherapy alone. METHODS AND STUDY DESIGN We included 53 patients with stage Tis, T1, and T2 laryngeal cancer who were irradiated in our department. Paraffin blocks of all biopsy specimens were subjected to immunohistochemical analysis with a bcl-2 oncoprotein mouse clone 124 Scytek kit. RESULTS The mean follow-up time was 61 months (range, 7-166). Local-regional recurrence was observed in 10 (19%) patients. Forty-three patients (81%) had negative bcl-2 staining, 5 patients (9%) had + staining, 3 patients (6%) ++ staining, and 2 patients (4%) +++ staining. No relationship was detected between bcl-2 expression and local control or overall survival. The emergence of a recurrence and a younger age (<50 years) were significantly related to poor overall survival (P = 0.000 and P = 0.021, respectively). Patients with hemoglobin levels in the middle of radiotherapy and at the end of radiotherapy higher than 13 g/dl had improved overall survival in multivariate analyses (P = 0.002 and P = 0.001, respectively). Regarding local control, the following were poor prognostic factors: smoking more than 20 cigarettes a day (P = 0.001) and being younger than 50 years of age (P = 0.001). CONCLUSIONS No correlation was observed between bcl-2 expression and local control or overall survival. Whereas hemoglobin level, age and existence of a recurrence had a prognostic impact on overall survival, patient age and smoking status influenced local control rates.


Bosnian Journal of Basic Medical Sciences | 2018

Prediction of breast cancer metastasis risk using circulating tumor markers: A follow-up study

Sibel Kahraman Cetintas; Gulcin Tezcan; Berrin Tunca; Unal Egeli; Mustafa Sehsuvar Gokgoz; Gulsah Cecener

Distant organ tumor dissemination is a major cause of breast cancer-related deaths. In 2010, we analyzed the prognostic importance of the circulating tumor markers (CTMs) cytokeratin 19 (CK19), CK20, epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) in relation to the clinical and pathological characteristics of patients with breast cancer (BC). To assess the clinical utility of CK19, CK20 and EGFR in predicting distant metastasis in BC, here we report 7-year follow-up results of 77 patients. The patients with at least one positive CTM were classified as CTM(+) and those negative for all CTMs were assigned to CTM(-) group. In patients who received no treatment following CTM analysis, 25.0% had metastasis in CTM(+) and 10.0% in CTM(-) group. In patients who received one of the following therapies: chemotherapy, radiotherapy or hormone therapy, or the combinations of these therapies, the rate of metastasis was 33.3% in CTM(+) and 20.0% in CTM(-) group. Disease-free time was shorter in CTM(+) patients compared to CTM(-) group (28.83 ± 10.76 and 41.38 ± 9.5 months, respectively). According to multivariate Cox proportional hazard regression analysis, the presence of regional lymph node metastasis, Ki-67 expression, higher tumor grade and CTM expression status were predictors of poor prognosis associated with distant metastasis (p < 0.05). Also, CTM positivity was a factor associated with metastasis-related poor prognosis (HR = 0.492, p = 0.026). The mean survival for CTM(+) patients was shorter than that for CTM(-) patients (90.671 ± 2.66 and 101.23 ± 3.92 months, respectively; p > 0.05). Our findings demonstrate that CTM positivity may indicate a high metastasis risk; however, CTM negativity does not guarantee low metastasis risk. These results may encourage further preclinical investigation of CTMs, to evaluate the possible implications of these findings to the clinical setting.


Bosnian Journal of Basic Medical Sciences | 2017

Enhancer of zeste homologue 2 (EZH2) expression in synovial sarcomas as a promising indicator of prognosis

Ulviye Yalcinkaya; Nesrin Ugras; Gonca Özgün; Gokhan Ocakoglu; Adem Deligonul; Sibel Kahraman Cetintas; Muhammed Sadık Bilgen

Synovial sarcoma (SS) is a type of soft-tissue sarcoma, often linked to poor survival. Although overexpression of enhancer of zeste homologue 2 (EZH2) has been associated with poor prognosis in different tumors, a few studies investigated this link in SS. Here, we analyzed the relationship between EZH2 expression and prognostic factors in SS. We included 29 patients with SS. Immunostaining of EZH2 was performed with (D2C9) XPTM Rabbit mAb antibody, and the results were classified as low EZH2 expression (negative or weak expression) and high EZH2 expression category (moderate or strong expression). Analysis of survival in relation to prognostic factors was performed with Kaplan-Meier survival curves and Cox proportional hazard regression analysis. Our sample included 19/29 female and 10/29 male patients, with age range 16-63 years. The tumor diameter ranged from 2 to 15 cm. Necrosis was observed in 15/29 cases. Sixteen cases had >10 mitoses per 50 high-power fields (HPFs). Out of 29 cases, 14 showed low and 15 had high EZH2 expression. Statistically significant results were obtained for the association between the presence of metastasis and necrosis (p = 0.042), high EZH2 expression and distant metastasis (p = 0.018), high EZH2 expression and necrosis (p = 0.016), and high EZH2 expression and the tumor size >5 cm versus tumor size ≤5 cm (p = 0.014). Patients with all of the following: the tumor size ≤5 cm, low EZH2 expression, and without necrosis and distant metastasis had significantly longer survival time. Our results are consistent with previous studies, suggesting that EZH2 overexpression is an indicator of poor prognosis in SS.


Balıkesir Üniversitesi Fen Bilimleri Enstitüsü Dergisi | 2017

Evre I larinks kanseri tedavisinde 3 ve 5 Alan Yoğunluk Ayarlı Radyoterapi (3A-YART, 5A-YART) tekniklerinde karotis arterin dozimetrik olarak karşılaştırılması

Ebru Cantürk; Gözde Topgül; Orhan Gürler; Sema Tunç; Candan Demiröz Abakay; Meral Kurt; Sibel Kahraman Cetintas

Bu calismada, radyoterapi (RT) uygulanmis Evre I larinks kanserli 18 hastanin arsiv materyali tedavi planlama sisteminden retrospektif olarak temin edilmistir. Bu hastalara ait planlama amaciyla cekilmis bilgisayarli tomografi (BT) verileri kullanilarak MONACO 5.1 tedavi planlama sistemi ile hastalarin 3 Alan Yogunluk Ayarli Radyoterapi (3A-YART) ve 5 Alan Yogunluk Ayarli Radyoterapi (5A-YART) tekniklerinin sanal tedavi planlari olusturulmustur. Klinik Hedef Hacime (CTV) 63 Gy/fx toplam doz tanimlanmistir. Tum tedavi planlari CTV’ yi kapsayacak sekilde tanimlanan dozun %95’ine normalize edilmis ve inhomojenite duzeltmeleri yapilmistir. Sanal planlar, sag ve sol karotis arter icin doz degerleri doz volum histogramlari (DVH) kullanilarak karsilastirilmistir. Elde edilen veriler Sosyal Bilimler icin Istatistiksel Paket Programi (SPSS) kullanilarak analiz edilmistir.


Archive | 2013

Simulation and Patient Fixation Methods

Sibel Kahraman Cetintas; Lutfi Ozkan; Sema Gozcu; Ali Altay

Radiotherapy (RT) for breast cancer patients, the appropriate indications and use of modern methods has been confirmed positive contributions that disease, disease-specific and overall survival in meta-analysis [1, 2]. The aim of RT is homogeneous distribution of the dose required for tumor control (±5%) at the target volume while protecting healthy tissue [3]. RT techniques can be difficult and vary depending on the anatomic structure of the region to be irradiated (breast, chest wall, or regional lymphatic) that target volumes could be in different depths and geometries [3–5]. Over time, with technologic advances and increasing experience in clinical practice, different simulation and treatment techniques have been developed [6–17]. Beginning in the 1950s, use of megavoltage treatment equipment in modern RT processes has reached a new point, with the use of magnetic resonance imaging, positron emission tomography, and computed tomography (CT) for treatment planning and in determining the target volumes. In a realistic virtual environment, a large number of techniques can be reviewed and an optimal technique can be formed using modern planning computers. Intensity modulated radiotherapy is becoming increasingly popular for critical organ volumes and dose reductions better than for target volume can be achieved [18, 19].


Leukemia & Lymphoma | 2006

Superior vena cava syndrome: Initial presentation of acute myeloid leukemia (AML-M0) with near-tetraploidy+/TdT+/CD7+/CD34+/HLA-DR+

Ridvan Ali; Fahir Ozkalemkas; Omer Yerci; Tulay Ozcelik; Cengiz Gebitekin; Vildan Ozkocaman; Atilla Ozkan; Ferah Budak; Tuna Gulten; Sibel Kahraman Cetintas; Ahmet Tunali

carcinoma patient with lung metastases in whom FDG PET showed increased uptake in the metastatic foci but not in the primary lesion. In conclusion, FDG PET results in our case suggest that FDG PET can clearly identify skeletal involvement. Also, FDG PET can detect some extraskeletal lesions such as muscle involvement and retro-ocular lesions. The role of FDG PET imaging in evaluation of extra-osseous lesions needs further investigation.

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