多药耐药蛋白4与直肠癌放疗敏感性关系的初步研究

目的 探讨多药耐药蛋白4 (MRP4)与直肠癌放疗敏感性之间的关系。方法 收集2000年1月至2009年1月期间95例进展期直肠癌患者放疗后进行手术的临床资料，采用免疫组织化学方法检测存档蜡块组织MRP4及P53蛋白表达，通过Logistic回归分析寻找直肠癌放疗的敏感因素。结果 95例患者中有40例(42％)对放疗敏感，其中有10例(11％)患者达到病理完全缓解，有55例(58％)患者对放疗不敏感。MRP4低表达者放疗敏感率为66.7％ (24/36)，高于MRP4高表达者(29.1％,16/59) (P＜0.05)；P53低表达者放疗敏感率为63.9％( 23/36)，高于P53高表达者(28.8％，17/59) (P＜0.01)。长程放疗者的放疗敏感率为83.3％ (20/24)，高于短程和中程放疗者[(31.3％，5/16)和(27.3％，15/55)](P＜0.01)。多因素回归分析显示：放疗方案、P53及MRP4蛋白表达均是影响直肠癌放疗敏感性的独立因素(P＜0.05)。结论 MRP4可作为直肠癌术前放疗敏感性预测的指标之一。

Preliminary studv on relationship between multi-drug resistance-associated protein 4 and radiosensitivity of rectal cancer

Objective To explore the correlation between multi-drug resistance-associated protein 4(MRP4) and the sensitivity of rectal cancer to radiation. Methods A total of 95 patients with advanced rectal cancer and received radiation therapy between January 2000 and January 2009. MRP4 and P53 protein expression in the paraffin-embedded specimen were detected by immunohistochemistry.Logistic regression analysis was used to evaluate factors associated with the sensitivity of rectal cancer to radiation. Results Forty patients(42％) were sensitive to radiation therapy, of whom 10(11％) achieved pathological complete remission. Fifty-five patients were (58％) not responsive to radiation. Patients with low expression of MRP4 had a 66.7％(24/36) response rate, significantly higher than that of patients with high MRP4 expression (29.1％,16/59)(P＜0.05). Patients with low expression of P53 had a 63.9％(23/36) response rate, significantly higher than that of patients with high P53 expression (28.8％,17/59)(P＜0.01). The response rate after long course radiation therapy was 83.3％(20/24), significantly higher than that of patients who underwent short and medium course radiation [(31.3％ ,5/16) and (27.3％, 15/55)] (P＜0.01). Multivariate Logistic regression analysis showed radiation regimen, the expression of P53 and MRP4 protein were independently associated with the sensitivity of rectal cancer to radiation (P＜0.05). Conclusion MRP4 may serve as a predictive marker for the sensitivity of rectal cancer to preoperative radiation.