目的　探讨术前化疗对肾母细胞瘤瘤体大小及瘤体耐药的影响。方法　本组 37例 ,术前影像学分期 ,Ⅰ～Ⅱ期 ,手术切除 ;Ⅲ～Ⅴ期 ,术前化疗 2～ 6周。免疫组化检测术后瘤体组织P 糖蛋白 (P glycoprotein ,P gp)、谷胱甘肽 硫转移酶 (glutathione s transferase π ,GST π)、拓扑异构酶Ⅱ(topoisomeraseⅡα ,TOPOⅡ )表达状况。结果　影像学分期 ,Ⅰ～Ⅱ期 2 0例 ,Ⅲ～Ⅴ期 17例。术前化疗组 ,瘤体缩减率 :1～ 2周为 (18.84± 3.5 4 ) %、3～ 4周为 (10 .78± 4 .2 6 ) %、5～ 6周为 (3.18±1.0 8) % ;瘤体GST π、TOPOⅡ表达阴性。瘤体在术前化疗 2周以内无P gp表达 ,4周以内有或弱阳性表达 ,4周以后P gp表达阳性。 结论　术前化疗应针对Ⅲ～Ⅴ期患儿 ,瘤体缩小主要集中于化疗 4周以内 ,超过 4周瘤体缩小不明显 ,且有引起肿瘤耐药的可能 Objective To investigate the effect of preoperative chemotherapy on tumor size and tumor drug resistance of nephroblastoma. Methods The group of 37 cases, preoperative imaging staging, Ⅰ ~ Ⅱ, surgical resection; Ⅲ ~ Ⅴ, preoperative chemotherapy for 2 to 6 weeks. The expression of P glycoprotein (P gp), glutathione S transferase π (GST π) and topoisomerase Ⅱ α (TOPO Ⅱ) in tumor tissue were detected by immunohistochemistry. Results Imaging staging, Ⅰ ~ Ⅱ 20 cases, Ⅲ ~ Ⅴ 17 cases. In the preoperative chemotherapy group, the reduction rate of the tumor was (18.84 ± 3.54)% in 1 ~ 2 weeks, (10.78 ± 4.226%) in 3 ~ 4 weeks and (3.18 ± 1.08) in 5 ~ 6 weeks )%; Tumor GST π, TOPO Ⅱ negative expression. There was no P gp expression in the tumor within 2 weeks before surgery, with or without positive expression within 4 weeks and P gp positive after 4 weeks. Conclusions Preoperative chemotherapy should be aimed at children with stage Ⅲ ~ Ⅴ, shrinkage of the tumor mainly concentrates within 4 weeks of chemotherapy, tumor shrinkage is not obvious more than 4 weeks, and may cause drug resistance of the tumor