| Objective:Nasopharyngeal Carcinoma (NPC) is very common in southern China. Since more than 90% of the tumors are poorly differentiated squamous cell carcinoma which is moderately radiosensitive, radical radiation therapy is the first choice of treatment. In clinic practice, we observed individualization of the reaction to radiotherapy in patients of the same histopathologic type, tumor staging and receiving the same treatment. Most of the patients are radiosensitive, while a few patients are radio-resistant which results in tumor residual and recurrence. This phenomenon indicates hetero-radiosensitivity may exist in different patients. In this study we propose to explore the latent mechanism involved in radioresistance of nasopharyngeal carcinoma in general level with proteomics technology to seek effective molecule markers that predict tumor radiosensitivity before radiotherapy and effective target molecule for radiosensitization gene therapy.Methods:(1) To establish tissue specimen bank and clinical information database of nasopharyngeal carcinoma, curative effects were observed and follow up was carried out. 8 strictly paired radiosensitive and radioresistant specimens were selected for proteomics analysis.(2) Total proteins were extracted from nasopharyngeal carcinoma tissues of radio-sensitive and radio-resistant specimens and were separated by immobilized PH gradient two-dimensional gel electrophoresis to establish the expression maps of proteomics. The differential expressed proteins between the two groups were analyzed with PDQuest image analysis software, and identified with MALDI-TOF-MS (matix-assisted laser desorption/ionization time of flight mass spectrometry).(3) Construct tissue microarrays including 14 chronic nasopharyngitis specimens and 158 nasopharyngeal carcinoma specimens with self-made simple tools and water-flatten-transferring method. The nasopharyngeal carcinoma specimens included 46 radio-sensitive specimens and 23 radio-resistant specimens.(4) Differentially expression level of selected proteins was detected by Immunohistochemistry analysis with tissue microarrays (TMAs).Results:(1) Tissue specimen bank and clinical information database of nasopharyngeal carcinoma were successfully constructed. More than 500 patient's clinical information was included in the information database which provides conveniences for subsequent research.(2) Two-dimensional gel electrophoresis profiles with clear background, well reproducibility and high quality were obtained. Twelve specially expressed proteins were identified to be related to radiosensitive. 8 spots (TSP-1, PK--M2, Human Electron Transfer Flavoprotein, MRP一14, D J-l, GMFG protein, prohibitin, Cytochrome c oxidase) expressed highly in radio-sensitive group and 4 spots (Mn-SOD, Erp29, GST omega 1, HSP27) expressed highly in radio-resistant specimens.(3) High-qualified 72-spots and 100-spots TMAs whose total effective rate is 95.9% were successfully constructed.(4) Research on the increased expression level of MnSOD, ERp29 and HSP27 in radio-resistant specimens with TMAs proved significant difference (P＜0.05) The prediction sensitivity to radiosensitvity of NPC of MnSOD, ERp29 and HSP27, were 84.62%, 81.81% and 47.37% separately; and the prediction specificity were 78.57%, 77.19% and 83.87% separately.Conclusion:(1) Based on the previous research, we improved the technique to construct high qualified NPC TMAs with self-made, simple tools and water-flatten-transferring method.(2) The high expression level of MnSOD, ERp29 and HSP27 in radioresistant NPC tissues indicates they may play an important role in the mechanism of radio-resistance in nasopharyngeal carcinoma. (3) MnSOD and ERp29 could be used as indicator to predict the radiosensitivity of NPC. MnSOD, ERp29 and HSP27 could be used as effective molecule target for gene therapy of radiosensitization.
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