外放射对鼻咽鳞癌P 糖蛋白的影响

 目的 初步探讨放射治疗前、后鼻咽鳞癌组织P-糖蛋白（P-gp）的表达及变化特点。方法 应用免疫组织化学SP法检测了48例初治鼻咽鳞癌患者放射治疗前、后P-gp的表达。结果 48例初治鼻咽鳞癌组织P-gp阳性表达率放射治疗前为18．75％（9例／48例），其中低分化鳞癌和中高分化鳞癌分别为17．65％（6例／34例）和21．43％（3例／14例）；放射治疗后P-gp阳性表达率为75．00％（36例／48例），其中低分化鳞癌和中高分化鳞癌分别为79．41％（27例／34例）和64．29％（9例／14例）。放射治疗后P-gp阳性表达率较放射治疗前呈增高趋势，放射治疗后P-gp阳性率和放射治疗前相比有显著性差异（P〈0．001）。结论 放射治疗可诱导和加强鼻咽鳞癌组织中P-gp表达，这可能是引起放、化疗交叉耐药的原因之一。

Effect of Radiation on p-glycoprotein Expression in Nasopharyngeal Squamous Carcinoma

Objective 　To investigate preliminarily the expression of p-glycoprotein ( P-gp) in patients with nasopharyngeal squamous carcinoma (NPSC) pre- and post-radiotherapy. Methods 　The immunohistochemistry with one monoclonal antibody JSB-1 staining was performed to test the expression of pgp in pre- and post-radiotherapy NPSC specimens from 48 patients . Results 　The positive rate of P-gp expression in the patients with NPSC pre-radiotherapy was 18. 75 %(9/ 48) . Among them , the positive expression rate was 17. 65 %(6/ 34) and 21. 43 %(3/ 14) in low grade differentiation squamous cell carcinoma and mid-high grade differentiation squamous cell carcinoma , respectively. The positive expression rate of post-radiotherapy was 75. 00 %(36/ 48) and among them , the positive expression rate was 79. 41 %(27/34) 、64. 29 %(9/ 14) in low grade differentiation squamous cell carcinoma and mid2high grade differentiation squamous cell carcinoma ,respectively. P-gp expression rate post-radiotherapy was significantly higher than that of pre-radiotherapy ( P < 0. 001) . Conclusion 　Our study indicates that pgp expression in NPSC was significantly induced by radiation and increases the overexpression of P-gp. Therefore , irradiation may be one of the reasons of crossed resistance to chemotherapy and radiotherapy.