Napovedni pomen označevalca rakavih matičnih celic NANOG pri seroznem adenokarcinomu jajčnika

Kenda Šuster, Nataša (author), Smrkolj, Špela (mentor), Virant Klun, Irma (comentor)

Izhodišče Patogeneza raka jajčnikov še vedno ni jasna. Novejše raziskave kažejo, da bi bile lahko za nastanek, razvoj in ponovitev tumorja po zdravljenju odgovorne rakave matične celice. Te tako kot embrionalne matične celice izražajo označevalce pluripotentnosti. NANOG je ključni transkripcijski dejavnik za uravnavanje samoobnavljanja in pluripotentnosti v embrionalnih matičnih celicah, izraža pa se tudi v različnih tumorjih, vključno z epitelijskim rakom jajčnikov. Namen naše raziskave je bil ovrednotiti izražanje označevalca NANOG pri bolnicah s seroznimi tumorji jajčnikov in pri seroznih karcinomih jajčnikov ter le-to primerjati s patohistološkimi in kliničnimi napovednimi kazalci. Preiskovanke in metode Prvi del raziskave je potekal retrospektivno, del prospektivno. V retrospektivnem delu raziskave smo izražanje označevalca NANOG določali z imunohistokemično metodo na tkivni mreži, zgrajeni iz arhiviranega tkiva jajčnikov. V raziskavo smo vključili 20 bolnic s seroznim benignim tumorjem jajčnikov, 30 bolnic s seroznim atipično proliferativnim (angl. borderline) tumorjem jajčnikov in 109 bolnic s seroznim karcinomom jajčnikov. Imunohistokemično reakcijo smo točkovali na osnovi intenzivnosti ter deleža obarvanega tumorja in na osnovi seštevka tumorje razdelili v štiri skupine: NANOG negativno (0), NANOG blago pozitivno (+1), NANOG zmerno pozitivno (+2) in NANOG močno pozitivno (+3) skupino. Za bolnice s karcinomom jajčnikov smo pridobili tudi klinične podatke in jih primerjali med omenjenimi skupinami. 20 tkivnih vzorcev seroznega karcinoma jajčnikov smo dodatno IHK barvali še na označevalca pluripotentnosti SOX2 in SSEA-4 ter označevalec za mezenhimske celice vimentin. V prospektivnem delu raziskave smo izražanje označevalca NANOG določali v 17 intraoperativno pridobljenih vzorcih seroznega tumorja jajčnikov. Poleg imunohistokemične metode smo pri tem uporabili tudi metodo prenosa western. Za analizo primerjave rezultatov obeh metod smo izračunali korelacijski koeficient. Rezultati V skupini arhiviranih vzorcev 159 seroznih tumorjev jajčnikov je bilo imunohistokemično NANOG pozitivnih 78 (49,1 %) tumorjev. Vsi NANOG pozitivni tumorji so bili patohistološko karcinomi visoke stopnje malignosti (p < 0,001). Vsi karcinomi nizke stopnje malignosti, vsi atipični proliferativni tumorji ter vsi benigni tumorji so bili NANOG negativni. Med karcinomi visoke stopnje malignosti je bilo NANOG pozitivnih 78 (73,6 %) tumorjev, od tega 24 (22,6 %) blago, 29 (27,4 %) zmerno in 25 (23,6 %) močno pozitivnih. Izražanje označevalca NANOG med seroznimi tumorji jajčnikov je bilo statistično značilno povezano z neugodnimi patohistološkimi napovednimi kazalci, to je stopnjo malignosti. Statistično značilne povezave s kliničnimi napovednimi kazalci, to je s starostjo bolnic, stadijem bolezni, ostankom tumorja po citoreduktivni operaciji, odzivom bolezni na kemoterapijo in preživetjem, pa nismo našli. Za neodvisna napovedna kazalca preživetja smo potrdili le stadij bolezni (p = 0,023) in ostanek tumorja po radikalni operaciji (p < 0,001). Rezultati prospektivnega dela raziskave so pokazali, da je imunohistokemično barvanja na NANOG pri bolnicah s seroznim tumorjem jajčnikov v statistično značilni korelaciji z rezultati metode prenosa western (p < 0,001). Dodatno smo s svetlobnim mikroskopom v povrhnjem epiteliju seroznega karcinoma jajčnikov zaznali spremembe, podobne epitelijsko-mezenhimski tranziciji, pri kateri se matičnim celicam podobne celice, pozitivne na označevalce pluripotentnosti, spreminjajo v rakavim matičnim celicam podobne celice, ki so poleg na označevalce pluripotentnosti pozitivne tudi na vimentin. Zaključek Imunohistokemična metoda je primerna diagnostična metoda določanja označevalca NANOG v tumorskih celicah bolnic s seroznimi tumorji jajčnikov. Imunohistokemično izražanje označevalca NANOG v tumorskih celicah pri bolnicah s seroznimi tumorji jajčnikov je bilo statistično značilno povezano s karcinomi visoke stopnje malignosti. Statistično značilne povezave med izražanjem označevalca NANOG in kliničnimi napovednimi kazalci nismo potrdili. S svetlobnim mikroskopom zaznane spremembe podobne epitelijsko-mezenhimski tranziciji, ter nastanek celic podobnih rakavim matičnim celicam, odpirajo novo področje za nadaljnje raziskave.

• Language: Slovenian
• Keywords: NANOG, rakave matične celice, serozni karcinom jajčnikov
• Work type: Doctoral dissertation
• Organization: MF - Faculty of Medicine
• Year: 2018
• PID: 20.500.12556/RUL-105154
• Publication date in RUL: 31.10.2018

KENDA ŠUSTER, Nataša, 2018, Napovedni pomen označevalca rakavih matičnih celic NANOG pri seroznem adenokarcinomu jajčnika [online]. Doctoral dissertation. [Accessed 26 March 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=105154

Secondary language

• Language: English
• Title: Predictive value of the cancer stem cell related marker NANOG in ovarian serous carcinoma

Abstract

Background The ovarian cancer pathogenesis is still unknown. According to recent data, it is possible that cancer stem cells are responsible for formation, progression and tumor repetition after the treatment has been completed. Same as embryonic stem cells, cancer stem cells express markers of pluripotency. NANOG is a key transcription factor that regulates self-renewal and differentiation in embryonic stem cells; its expression was also detected in different tumors, one of them being ovarian carcinoma. The purpose of our study was to assess NANOG expression in different ovarian serous tumors, and in case of ovarian serous carcinoma to evaluate its significance for prognosis of disease. Patients and methods The first part of the study was retrospective, and the second part was prospective. In the retrospective part NANOG expression was immunohistochemically analyzed in the ovarian tissue microarrays. The microarrays were constructed from archived ovarian tissue of 109 ovarian serous carcinoma patients, 30 borderline ovarian serous tumor patients, and 20 benign ovarian serous tumor patients. Immunohistochemical reaction in tumor tissue samples was scored based on percentage of positive cells and signal intensity of tumor cells. According to acquired scores we classified tumor samples into four groups: NANOG – negative group (0), NANOG - slightly positive group (+1), NANOG - moderately positive group (+2) and NANOG - strongly positive group (+3). For ovarian serous carcinoma patients clinical data was acquired, and correlation between NANOG expression and clinical parameters was analyzed. 20 tissue samples of ovarian serous carcinoma were further immunohistochemically stained for markers of pluripotency SOX2, SSEA-4 and marker of mesenchymally-derived cells vimentin. In prospective part of our study Western blot and immunohistochemistry were performed for assessment of NANOG expression in 17 intraoperatively obtained tissue samples of ovarian serous tumors and the correlation between the results were analyzed. Results Out of 159 ovarian serous tumors, NANOG was positive in 78 (49.1%) cases. All NANOG positive tumors were high grade carcinomas (p < 0.001). All low grade carcinomas, all borderline tumors and all benign tumors were NANOG negative. In terms of high grade carcinoma group 78 (73.6%) were NANOG positive: 24 (22.6%) slightly positive, 29 (27.4%) moderately positive and 25 (23.6%) strongly positive. All cases, where NANOG was positively expressed presented high grade morphology. NANOG expression showed no significant correlation with clinical parameters such as age of patients, stage of disease, tumor residue after radical surgery, chemotherapy efficiency and survival. The only independent prognostic factors were stage of disease (p = 0.023) and tumor residue (p < 0.001). We proved immunohistochemistry to be reliable method for NANOG assessment in case of ovarian serous tumors as significant correlation (p < 0.001) between the results of Western blot and immunohistochemistry were confirmed. Using light microscope, changes similar to epithelial-mesenchymal transition were observed in ovarian surface epithelium of patients suffering from ovarian serous carcinoma. These changes might generate putative cancer stem cells positive for markers of pluripotency and vimentin. Conclusions Immunohistochemistry was proved to be an adequate method for NANOG expression assessment. NANOG expression in ovarian serous tumor cells statistically significantly correlated with high grade ovarian serous carcinoma. Our results showed no statistically significant correlation between NANOG expression and clinical parameters. Changes similar to epithelial-mesenchymal transition and generation of putative cancer stem cells observed by light microscope need further research and clarification.

• Keywords: NANOG, cancer stem cells, ovarian serous carcinoma