and provided protection against the disease. Conclusion: Our findings showed that hOGG1-Ser326Cys Cys allele is statistically important and relevant with respect to the development of oral squamous cancer. In view of our results, further studies including expression levels are required in which hOGG1-Ser326Cys should be investigated as molecular biomarkers for the early prediction of squamous cell carcinoma. Introduction Head and neck cancer accounts for about 5% of all malignant tumors and is

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... he sixth most common tumor [1] . Tumors in head and neck regions comprise the oral cavity, skin, nasal cavity and paranasal sinuses, nasopharynx, lips, oropharynx, larynx, hypopharynx and cervical esophagus, cervical trachea, neck, salivary glands, and parapharyngeal space. Oral squamous cell carcinoma (OSCC) is most common with 90% range of the oral cavity disease [2] [3] [4] . Many factors have been identified in the cancer development process, such as biological and environmental factors, as well as smoking habits and alcohol exposure [1, 5] . Smoking and alcohol are related to oral cav-Abstract Background: Oral squamous cell carcinoma (OSCC) is one of the most widespread cancer types that arise from different sites of oral cavity and has a 5-year survival rate. This study is aimed at investigating the human oxoguanine glycosylase 1 (hOGG1)-Ser326Cys and APE-Asp148Glu polymorphisms of DNA repair genes in OSCC. Materials and Methods: We investigated the hOGG1-Ser326Cys and APE-Asp148Glu polymorphisms of DNA repair genes in the oral cavity. Genotyping was conducted using polymerase chain reaction-restriction fragment length polymorphism analysis based on 132 patients who were diagnosed as having OSCC and 160 healthy subjects. Results: Individuals with the genotype hOGG1-Ser326Cys, Cys allele carriers, were found significantly more frequently in the patient group compared to the control group as increase in risk (p < 0.001). Furthermore, it was observed that there were significantly more individuals with the Ser allele in the control group (p < 0.001). Individuals with genotype APE-Asp148Glu were not statistically significant; however, they were still more in the control group