Dissertation committee:
Νικόλαος Νικητάκης Αναπληρωτής Καθηγητής (επιβλέπων),Κωνσταντίνος Τόσιος Επίκουρος Καθηγητής, Αλεξάνδρα Σκλαβούνου Καθηγήτρια
Summary:
Objectives: The aim of this study was to investigate the immunohistochemical
expression of upstream mTOR activators and downstream mTOR targets in benign
and malignant salivary gland neoplasms (SGNs).
Materials and Methods: Tissue samples consisted of 39 malignant and 13 benign
minor SGNs of various histological subtypes, and 8 control cases of normal
minor salivary
glands.
An immunohistochemical analysis for 4E-BP1, p4E-BP1, S6, pS6, pAKT and
eIF4E was performed on all tissue samples.
Results: pAKT was expressed in the cytoplasm of tumor cells. Positive
immunostaining for pAKT was found in normal salivary glands (75% ) and in all
benign and malignant
tumors.
4EBP1 exhibited mainly cytoplasmic immunoreactivity and was observed in normal
salivary glands (87.5%) and in all benign and malignant tumors.
p4EBP1 was both cytoplasmic and nuclear. Positive immunoreactivity for
p4EBP1was found in 97.4% of malignant cases and in all benign cases, while it
was negative in all control cases.
S6 immunohistochemical expression was only cytoplasmic. Among normal salivary
glands, 37.5% of cases were positive for S6. Positive S6 immunoreactivity was
found in 92.3% of benign cases, and in all malignant SGNs.
pS6 was found in the cytoplasm of tumor cells. All normal salivary glands were
negative. pS6 immunostaining was found in 77% of benign salivary gland tumors
and in 95% of malignant .
eIF4E was expressed in the cytoplasm of tumor cells. Possitive immunostaing for
eIF4E was expressed in only 1 case of normal salivary gland. eIF4E was observed
in 69.2% of benign tumors and in 76.9% of malignant tumors.
The expression of all the above molecules was higher in malignant cases,
compared to benign and normal salivary gland.
Conclusion: The mTOR signaling pathway seems to be activated in SGNs. Further
investigations are necessary for using the expression of them as diagnostic or
therapeutic markers.
