Unit:
Department of ChemistryLibrary of the School of Science
Author:
Giannopoulou Lydia
Dissertation committee:
Ευρύκλεια Λιανίδου, Καθηγήτρια, Τμήμα Χημείας, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών (Επιβλέπουσα Καθηγήτρια)
Ντία Γαλανοπούλου, Καθηγήτρια, Τμήμα Χημείας, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών (μέλος τριμελούς συμβουλευτικής επιτροπής)
Αικατερίνη Παυλάκη, Καθηγήτρια, Ιατρική Σχολή, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών (μέλος τριμελούς συμβουλευτικής επιτροπής)
Χρίστος Παπαδημητρίου, Καθηγητής, Ιατρική Σχολή, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών
Νικόλαος Θωμαΐδης, Καθηγητής, Τμήμα Χημείας, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών
Γεωργία Σωτηροπούλου, Καθηγήτρια, Τμήμα Φαρμακευτικής, Πανεπιστήμιο Πατρών
Χρήστος Κρούπης, Αναπληρωτής Καθηγητής, Ιατρική Σχολή, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών
Original Title:
Μελέτη δεικτών μεθυλίωσης στον καρκίνο των ωοθηκών
Translated title:
Study of methylation biomarkers in ovarian cancer
Summary:
Ovarian cancer is the fourth most common gynecological malignancy and the fifth leading cause of cancer-related mortality in women. It is characterized by a remarkable histological and molecular heterogeneity, with the main subtype being high grade serous ovarian carcinoma (HGSC). This doctoral thesis is focused on DNA methylation of selected genes in clinical samples of patients with HGSC. For all methylation studies, we recruited FFPE samples of primary tumors, adjacent morphologically normal tissues, as well as corresponding plasma samples from the same patients. For the evaluation of methylation, we used two different methodologies, a real-time methylation specific PCR (real-time MSP) for the detection of methylation in tumor and adjacent FFPEs, as well as plasma circulating tumor DNA (ctDNA), and a methylation-sensitive high-resolution melting analysis (MS-HRMA) for the semi-quantitative estimation of methylation in tumor and adjacent FFPEs.
At first, in a comparison study, we investigated RASSF1A promoter methylation status in primary tumors, adjacent morphologically normal tissues and corresponding plasma samples of patients with HGSC. In primary tumors and adjacent tissues, RASSF1A promoter methylation was significantly correlated with worse patients’ overall survival (OS). In this study, we reported for the first time that RASSF1A promoter methylation provides significant prognostic information in HGSC patients.
We next examined ESR1 methylation in primary tumors and ctDNA of patients with HGSC. In primary tumors, ESR1 methylation was significantly correlated with better patients’ OS and progression free survival (PFS). In this study, we attempted to clarify the role of ESR1 methylation in HGSC.
We next performed methylation studies of specific genes involved in molecular pathways which are frequently disrupted in HGSC, such as BRCA1 and MGMT genes involved in different ways in DNA repair, the NR2F1 gene that is actively involved in the establishment of a dormant phenotype, the RASSF10 gene involved in the development of chemoresistance and the RKIP gene involved in the EMT process. After the statistical analysis of the results, we observed a significant correlation between NR2F1 methylation in primary tumors with worse patients’ PFS. Furthermore, BRCA1 methylation in ctDNA was significantly correlated with better PFS.
Finally, we estimated PD-L1 gene expression in circulating tumor cells (CTCs) of patients with HGSC, using RT-qPCR. Based on the results of the study, a statistically significant association between PD-L1 gene expression and worse patients’ OS was observed, indicating a possible prognostic significance in HGSC.
Main subject category:
Health Sciences
Keywords:
Ovarian cancer, DNA methylation, Liquid Biopsy, circulating tumor DNA, Epigenetics
Number of references:
415
