Araştırma Çıktıları

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    Can Laws Be a Potential PET Image Texture Analysis Approach for Evaluation of Tumor Heterogeneity and Histopathological Characteristics in NSCLC?
    (SPRINGER, 2018-01-01) Karacavus, Seyhan; Yilmaz, Bulent; Tasdemir, Arzu; Kayaalti, Omer; Kaya, Eser; Icer, Semra; Ayyildiz, Oguzhan
    We investigated the association between the textural features obtained from F-18-FDG images, metabolic parameters (SUVmax(,) SUVmean, MTV, TLG), and tumor histopathological characteristics (stage and Ki-67 proliferation index) in non-small cell lung cancer (NSCLC). The FDG-PET images of 67 patients with NSCLC were evaluated. MATLAB technical computing language was employed in the extraction of 137 features by using first order statistics (FOS), gray-level co-occurrence matrix (GLCM), gray-level run length matrix (GLRLM), and Laws' texture filters. Textural features and metabolic parameters were statistically analyzed in terms of good discrimination power between tumor stages, and selected features/parameters were used in the automatic classification by k-nearest neighbors (k-NN) and support vector machines (SVM). We showed that one textural feature (gray-level nonuniformity, GLN) obtained using GLRLM approach and nine textural features using Laws' approach were successful in discriminating all tumor stages, unlike metabolic parameters. There were significant correlations between Ki-67 index and some of the textural features computed using Laws' method (r = 0.6, p = 0.013). In terms of automatic classification of tumor stage, the accuracy was approximately 84\% with k-NN classifier (k = 3) and SVM, using selected five features. Texture analysis of FDG-PET images has a potential to be an objective tool to assess tumor histopathological characteristics. The textural features obtained using Laws' approach could be useful in the discrimination of tumor stage.
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    LOW 06 METHYLGUANINE-DNA METHYTRANSFERASE (MGMT) AND PAN-CYTOKERATIN (PAN-CK) EXPRESSION VIA IMMUNOHISTOCHEMISTRY IN PITUITARY ADENOMAS
    (EDITURA ACAD ROMANE, 2017-01-01) Basaran, R.; Onoz, M.; Bolukbasi, F. H.; Efendioglui, M.; Sav, A.
    Introduction. Pituitary adenomas (PA) are the third most common intracranial tumors, with an incidence rate of 10-15\%. More than half are invasive, infiltrating adjacent structures. The primary objective of this project was to determine whether MGMT expression is associated with the invasiveness of PA. Material and Method. All patients who underwent surgical decompression consecutively between 20072012 were included. All data were obtained from the case records. Formalin-fixed paraffin-embedded (FFPE) tissue specimens were stained with hematoxylin and eosin (HE) and then examined via light microscope. Paraffin blocks that lacked necrosis and hemorrhage were chosen for histologic examination. In addition to an immunoprofile battery that consisted of Ki-67 and p53, MGMT, S-100 and Pan-CK were evaluated as well. Results. The subjects included 25 women and 15 men. The mean age was 48.9 +/- 14.5 years. Of these, 63\% of cases involved the invasion of adjacent structures. Of the PA, 17 (42\%) were non-functioning pituitary adenomas (NFPA). There was a statistically significant relationship between the invasiveness and Ki-67, p53, MGMT expression, and prolactinoma. Gonodotropinomas were mostly non-invasive. FPAs presented invasive features more frequently than NFPAs. Pan-CK was positive in GH-secreting adenomas but negative in FSH- and LH-secreting adenomas. Conclusion. Ki-67 and p53 in lower expression level can be used for evaluating invasiveness but not for recurrence. MGMT expression can be a useful IHC indicator for invasiveness. However, Pan-CK cannot be used for invasiveness or aggressiveness.