Browsing by Author "Gokoz, O"

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    Investigation of BRAF mutation analysis with different technical platforms in metastatic melanoma
    Sener, E; Yildirim, P; Tan, A; Gokoz, O; Tezel, GG
    In metastatic melanoma, the detection of somatic mutations in the BRAF gene is crucial regarding patient selection for targeted therapy. Several screening methods have been developed to identify BRAF gene mutations. In this study, our objective was to evaluate the detection of the BRAF V600 mutations using two molecular methods, real-time polymerase chain (real-time PCR) assay and pyrosequencing, and immunohistochemistry (IHC), and to compare the results of these different technical platforms. This study included 98 patients diagnosed with metastatic melanoma at the Hacettepe University, Department of Pathology between 2002 and 2014. BRAF mutation analysis was tested with real-time PCR, pyrosequencing and IHC methods. The results of all three tests were compared with a reference test, and the sensitivity, specificity rates and kappa coefficient values were analysed for each test. We successfully analysed BRAF mutations using all three methods in 92 patients. According to our findings, the pyrosequencing method had the highest kappa value regarding the determination of BRAF V600 mutations. The kappa values were at almost perfect agreement levels in pyrosequencing and realtime PCR assay (kappa coefficient for pyrosequencing = 0.895 (95% CI: 0.795-0.995); kappa coefficient for real-time PCR=0.871 (95% CI: 0.761-0.981). The kappa value was at a substantial agreement level in the IHC analysis (kappa coefficient = 0.776 (95% CI: 0.629-0.923). According to our results, we found that real-time PCR and pyrosequencing methods were equally excellent in determination of BRAF V600 mutations. The IHC method, which is commonly used in routine pathology practice, can also be safely used as a screening test for determination of BRAF V600 mutations. (C) 2017 Elsevier GmbH. All rights reserved.
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    A Retrospective Multicenter Evaluation of Cutaneous Melanomas in Turkey
    Gamsizkan, M; Yilmaz, I; Buyukbabani, N; Demirkesen, C; Demiriz, M; Cetin, ED; Ince, U; Akalin, T; Demirkan, NC; Lebe, B; Erdem, O; Gokoz, O; Sakiz, D; Demireli, PT; Astarci, HM; Adim, SB; Zemheri, IE; Acikalin, A; Yaman, B; Aydin, O; Bassorgun, CI
    Background: We defined melanoma distribution in a large series of Turkish patients and evaluated the prognostic parameters of melanomas. Materials and Methods: A total of 1574 patients' data was retrospectively collected at 18 centers in Turkey. Demographic characteristics were questioned and noted. Prognostic parametres were evaluated based on sentinel lymph node involvement. Results: Mean age was 56.7 (4-99) years. While 844 (53.6%) cases were male, 730 (46.4%) cases were female. One thousand four hundred forty-seven (92%) cases were invasive melanoma and 127 (8%) cases were in-situ melanoma. The most common histopathological form was the superficial spreading melanoma (SSM) which was found in 549 patients (37.9%). It was followed by nodular melanoma in 379 (26.2%), acral lentiginous melanoma (ALM) in 191 (13.2%) and lentigo maligna melanoma in 132 (9.1%), respectively. On univariate analysis, lymphovascular invasion (p<0.001), tumor thickness (p<0.001), histopathological subtype (p<0.001), Clark level (p=0.001), ulceration (p<0.001), >= 6/mm(2) mitosis (p=0.005), satellite formation (p=0.001) and gender (p=0.03) were found to be associated with sentinel lymph node positivity. Regression was associated with sentinel lymph node negativity (p=0.017). According to multivariate analysis, lymphovascular invasion and tumor thickness were significant independent predictive factors of SLN positivity. Patient age, tumor localization, precursor lesions, lymphocytic infiltration and neurotropism were not related with sentinel lymph node involvement. Conclusions: In this retrospective analysis, it was found that the prevalence of SSM is at a lower rate while the prevalence of ALM is at a higher rate when compared to western countries. According to Breslow index; most of the melanoma lesions' thickness were greater than 2 mm, corresponding Clark IV. Vascular invasion and tumor thickness are the most important factors for sentinel lymph node involvement.