الفهرس 
ACKNOWLEDGEMENT
Head And Neck CancerOnly 14 pages are availabe for public view
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Abstract
Head and neck cancer is the sixth most common cancer worldwide comprising 500,000 newly diagnosed cases each year. Head and neck squamous cell carcinoma (HNSCC) develops in the squamous epithelial cells of the upper aerodigestive tract, including the oral cavity, oropharynx, hypopharynx and larynx. Radiotherapy has an integral role in the treatment protocol but failure of radiotherapy has unfavourable outcome; with high incidence of postoperative complications So, the need for a biological marker to predict the response to radiotherapy before the start of treatment could improve the outcome of treatment. Regenerating gene-I (REG-I) has been studied in different gastrointestinal cancers and proved to be a marker of radiosensitivity.In our study, we aimed to examine the expression of REG-I in head and neck squamous cell carcinoma and its correlation with the response to radiotherapy. The study included 91 patients; Forty-five patients (49.5%) were diagnosed as early stage cancer (T1-T2) (15 laryngeal, 14 hypopharyngeal, 16 oral cavity and oropharyngeal), The other 46 (50.5%) were diagnosed as late stage cancer (T3-T4) (17 hypopharyngeal, 8 laryngeal, 21 oral cavity and oropharyngeal).>We obtained, from the medical records, the results of pretreatment endoscopy and positron emission computerized tomography (PET-CT), and staging was carried out according to the tumor-node-metastasis (TNM) classification .>Both early and late groups were evaluated after radiotherapy by positron emission computerized tomography (PET-CT) and endoscopic biopsy for evaluation of the clinical and histological response to radiotherapy depending on the Response Evaluation Criteria in Solid Tumors (RECIST) Guideline which was published in 2000 as a revision of the WHO criteria and also adopted by the Japan Society of Clinical Oncology. Then, we obtained the pretreatment endoscopic biopsy specimens from all patients (to avoid the effect of radiation on the specimens) and we assessed REG I protein expression by immunohistochemistry. Finally, we have examined the correlation between REG I expression and the response to radiotherapy. We found that, there is no statistically significant difference in the clinical response to radiotherapy between early and late stage groups (P=0.064), while there is a significant difference in the histological response to radiotherapy between both groups (P=0.036). We also found a statistically significant correlation between REG-I expression and both the clinical and histological response to radiotherapy in early (p value= 0.036 &0.001 respectively) and late (p value¬= 0.046 &0.002 respectively) stage cancer. from our results, we found that REG-I could be used as a biomarker of radiosensitivity in head and neck squamous cell carcinoma before the start of treatment to avoid the side effects of radiation specially in radioresistant cases.