Dissertation committee:
Ανδρέας Λάζαρης, Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Νικόλαος Καβαντζάς, Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Ευστράτιος Πατσούρης, Ομότιμος Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Αφροδύτη Νόννη, Αναπληρώτρια Καθηγήτρια, Ιατρική Σχολή, ΕΚΠΑ
Χαρίκλεια Γακιοπούλου, Αναπληρώτρια Καθηγήτρια, Ιατρική Σχολή, ΕΚΠΑ
Γεώργιος Αγρογιάννης, Αναπληρωτής Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Γεωργία Θωμοπούλου, Αναπληρώτρια Καθηγήτρια, Ιατρική Σχολή, ΕΚΠΑ
Summary:
Human papillomavirus (HPV) involvement in cervical carcinogenesis represents a classical template of analyzing viral-mediated carcinogenesis. High Risk (HR) HPV subtypes cause initially a simple (episomal) penetration in target host cells. Persistent HR-HPV infection leads to an HPV-DNA integration into the host cell genome resulting to an aberrant oncogene E6/E7 expression. MDM2, a proto-oncogene encoding for a nuclear-localized E3 ubiquitin ligase, acts as a major negative regulator in p53-MDM2 auto-regulatory pathway. MDM2 directly binds to p53 and represses its transcriptional activity and promotes p53 proteasomal degradation. Our aim was to investigate the role of abnormal p53/MDM2 protein co-expression in HPV-mediated cervical squamous intraepithelial lesions (SIL) and also the role of abnormal Cyclin D1 in them combined with p16INK4A expression. Eighty (n=80) cases characterized as SILs and also borderline ones with molecularly proven HPV infection were examined. Using liquid-based cytology, we constructed ten (n=10) slides each containing eight (n=8) cell spots. Immunocytochemistry (ICC) was performed using anti-Cyclin D1/MDM2/p16/p53 antibodies. Digital image analysis was also implemented for evaluating objectively the protein expression levels on the corresponding stained slides. Cyclin D1 protein over expression was observed in 8/80 (10%) cell spots, whereas low expression rates were detected in 72/80 (90%) cases. Cyclin D1 expression was strongly associated with the HPV type group (HR-HPV) (p=0.001) and borderline with the Cervical Intraepithelial Neoplasia (CIN) categorization (p=0.06). Concerning the influence of marker’s protein expression in SIL categorization, no statistical significance was identified (p=0.10). Cyclin D1 overexpression is observed in a sub set of SILs developed by HR-HPV persistent infection. Although SIL and CIN categorization seem to be not influenced by Cyclin D1 expression levels, mechanisms of gene’s deregulation should be a promising molecular target for discriminating specific genetic signatures in the corresponding initial cervical neoplastic lesions. P53 and especially MDM2 over expression is observed in a sub set of SILs developed by HR-HPV persistent infection in cervical epithelial host cells. SIL and CIN categorization seem to be strongly influenced by p53 expression levels, but not by MDM2 aberrant expression. p16 overexpression also represents a significant and useful biomarker for evaluating progression of SILs/CINs.
Keywords:
P16,P53,CyclinD1,MDM2,HPV infection,Cell spots analysis
