DNA base excision repair proteins APE‐1 and XRCC‐1 are overexpressed in oral tongue squamous cell carcinoma

• Published in: Journal of oral pathology & medicine Vol. 46; no. 7; pp. 496 - 503
• Main Authors: Santana, Thalita, Sá, Melka Coêlho, Moura Santos, Edilmar, Galvão, Hébel Cavalcanti, Coletta, Ricardo D., Freitas, Roseana de Almeida
• Format: Journal Article
• Language: English
• Published: Denmark Wiley Subscription Services, Inc 01-08-2017
• Subjects: Adolescent; Adult; Aged; Base excision repair; Carcinogens; Carcinoma, Squamous Cell - genetics; Carcinoma, Squamous Cell - mortality; Carcinoma, Squamous Cell - pathology; Cell Nucleus - genetics; Chemotherapy; Child; Cytoplasm; Cytoplasm - genetics; Deoxyribonucleic acid; Disease-Free Survival; DNA; DNA damage; DNA Repair; DNA-(Apurinic or Apyrimidinic Site) Lyase - genetics; Female; Genomes; Humans; Immunohistochemistry; Male; Middle Aged; Neoplasm Grading; Nuclei; Oral cancer; Proteins; Risk Factors; Squamous cell carcinoma; Survival; Tongue; Tongue Neoplasms - genetics; Tongue Neoplasms - mortality; Tongue Neoplasms - pathology; Tumors; Up-Regulation; X-ray Repair Cross Complementing Protein 1 - genetics; Young Adult; DNA repair; oral cancer; immunohistochemistry
• ISSN: 0904-2512; 1600-0714
• DOI: 10.1111/jop.12529

Background
DNA repair systems play a critical role in protecting the human genome from damage caused by carcinogens. Modifications in DNA repair genes may be responsible for tumor development and resistance of malignant cells to chemotherapeutic agents. The major pathway for oxidative DNA damage repair is the base excision repair pathway. This study aimed to assess the immunoexpression of DNA repair proteins APE‐1 and XRCC‐1 and its association with clinical, histologic, and survival parameters in oral tongue squamous cell carcinoma, to investigate a possible role for those proteins in tumor behavior.
Methods
The expression of APE‐1 and XRCC‐1 was evaluated by immunohistochemistry in 82 cases of oral tongue squamous cell carcinoma. Histopathological grading was performed for each case. Pearson's chi‐square and Fisher's exact tests were used to determine the association between protein expressions and clinicopathological features of tumors, whereas Kaplan–Meier curves and Cox regression were used to analyze disease‐specific and disease‐free survival. Statistical significance was set at P ≤ 0.05.
Results
APE‐1 was highly expressed in the nucleus and cytoplasm in 64.6% of cases, and XRCC‐1 showed overexpression only in the nucleus in 61% of cases. High expression of XRCC‐1 was significantly associated with tumors at early clinical stages (I and II, P < 0.01) and nodal status (P = 0.03). Both proteins were not associated with other clinical parameters, histopathological grading, or survival.
Conclusions
DNA base excision repair proteins APE‐1 and XRCC‐1 are upregulated in oral tongue squamous cell carcinoma, and XRCC‐1 expression is associated with better clinical staging and nodal status.