Evangelos Falidas1, Eirini Kitsiouli2, Dimitrios Tsounis3, Asimina Kalogirou4, Evangelos Tsiambas5, Paraskevi Tziakou6, George Tsouvelas7, Stylianos Papadopoulos2, Michail Mitsis9, Marilena Lekka2, Despoina Spyropoulou8, Konstantinos Vlachos9
1Department of Surgery, Halkida General Hospital, Halkida, Greece;
2Laboratory of Biochemistry, Chemistry Department, University of Ioannina, Ioannina, Greece;
3Department of Gastroenterology, 251 AF Hospital, Athens, Greece;
4Department of Pathology, Halkida General Hospital, Halkida, Greece;
5Department of Cytology, 417 VA (NIMTS) Hospital, Athens, Greece;
6Department of Pathology, “Thriasio” General Hospital, Elefsina, Greece;
7Department of Nursing, University of West Attica, Athens, Greece;
8Department of Radiation Oncology, Medical School, University of Patras, Greece;
9Department of Surgery, University Hospital of Ioannina, University of Ioannina, Ioannina, Greece
Summary
Purpose: Group III phospholipase A2 (PLA2G3) is a main member of proteins that are involved in functions such as fatty acid metabolism and oxidative stress response. Our aim was to investigate the expression of Prdx-6 in colon adenocarcinoma (CA).
Methods: A series of 30 formalin-fixed, paraffin-embedded primary CAs tissue sections were used and analyzed. Immunohistochemistry was performed using an anti-PLA2G3 antibody. Digital image analysis was also implemented for evaluating objectively the protein expression levels on the corresponding stained cells.
Results: PLA2G3 protein overexpression (increased immunostaining levels) was observed in 23/30 (76.6%) cases, whereas 07/30 (23.40%) CA tissues demonstrated low protein levels, respectively. PLA2G3 overall expression was strongly associated with the grade and tumor localization of the examined tumors (p=0.001, p=0.027, respectively), whereas other statistical significances were not assessed (inflammatory infiltration: p=0.846; stage: p=0.755; tumor diameter: p=0.300; ulceration: p=0.872; gender: p=0.902).
Conclusions: PLA2G3 overexpression is observed in a significant subset of CAs associated with aggressive biological behavior (neoplasm dedifferentiation) and also a kind of selectivity in localization of the malignant substrate. PLA2G3 seems to be an important enzyme for endogenous cell response to increased oxidative stress and fatty acid metabolic imbalances in CAs. For these reasons, it should be considered as a potential biomarker and therapeutic target in these malignancies.
Key words: carcinoma, colon, PLA2G3, immunohistochemistry, oxidative stress, metabolism.
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