Araştırma Çıktıları

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Author: search.filters.author.Tokat, FatmaSubject: search.filters.subject.immunohistochemistry

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    Primary pericardial extragastrointestinal stromal tumor: A case report and literature review
    (SPANDIDOS PUBL LTD, 2015-01-01) Arpaci, Taner; Tokat, Fatma; Arpaci, Rabia Bozdogan; Akbas, Tugana; Ugurluer, Gamze; Yavuz, Sinan
    Gastrointestinal stromal tumors (GISTs) are the most prevalent mesenchymal tumors of the gastrointestinal tract. GISTs are considered to originate from the interstitial cells of Cajal, the pacemakers of the peristaltic activity of the gastrointestinal tract. More than 95\% of GISTs express KIT protein and discovered on GIST-1. GISTs may also be encountered in locations outside the gastrointestinal tract, in which case they are referred to as extra-GISTs (EGISTs) and often behave more aggressively. This is the case report of a primary pericardial EGIST in a 53-year-old male patient, confirmed by immunohistochemistry. To the best of our knowledge, this is the third case of EGIST diagnosed above the diaphragm, without being associated with the esophageal wall. Two cases of primary EGIST arising from the pleura were reported previously. In addition, this is the first reported case of an EGIST originating from the pericardium.
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    Comparison of Two Different Antibody Clones of Programmed Cell Death Ligand 1 (PD-L1) with Immunohistochemical Method on Various Tumors
    (KARE PUBL, 2020-01-01) Tokat, Fatma
    Objectives: Programmed cell death ligand 1 (PD-L1) is the most important immune checkpoint protein in immune defense against tumors. PD-1/PD-L1 inhibitors are considered an option in cancer treatments. The evaluation of PD-L1 immunohistochemical staining is used as a biomarker to determine the decision and response of the use ofthese inhibitory drugs. There is a wide variety of clones and platforms for the PD-L1 antibody, and each pathology department uses different clones and platforms which causes confusion. Therefore, in this study, we evaluated the immunohistochemical staining of different clones in the same tumor. Methods: Overall, 90 cases comprising 47 lung, 11 breast, 9 colon, 6 stomach, and 7 pancreatic carcinomas and 10 other tumors were included in the study. Of these, 43 specimens were obtained by resection, 40 by tru-cut biopsy, and 7 by endoscopic biopsy. Sections prepared from formalin-fixed paraffin-embedded blocks were evaluated immunohistochemically with SP142 and SP263 clones. Results: In this study, we observed positive staining in 48.8\% (n=44) and negative staining in 51.2\% (n=46) among all cancers with SP263 clone, and positive staining in 33.3\% (n=30) and negative staining in 66.7\% with SP142 clone as well. This study also showed that compared to SP263, SP142 clone stained tumor cells less in lung, colon, stomach, pancreatic, and other carcinomas. Conclusion: In this study, we found different staining percentages for SP263 and SP142 in the same tumor. Pathologists conducting immunohistochemical studies for PD-L1 should indicate the staining percentages of tumors and the antibody clone they used in the reports. Meanwhile, oncologists should keep in mind which clone was stained, and that selecting SP142 is less positive to correct patients who can receive appropriate immunotherapy.