目的：探讨MEK/ERK通路蛋白在肾癌骨转移患者原发灶及转移灶表达的差异及其意义，并探索这种差异的发生机制。方法： 选择北京大学人民医院2009年1月至2010年1月 7例肾癌骨转移患者的原发灶及转移灶组织标本，应用免疫组织化学法分析VEGFR-2、MEK、ERK蛋白在原发灶与转移灶表达的差异，VEGFR-2、MEK、ERK的Ⅰ抗工作浓度（体积比）分别为1 ∶200、1 ∶25、1 ∶250，应用PCR技术检测PDGFRA基因20号外显子，K-ras基因2号外显子，Braf基因15号外显子和MEK1基因2号外显子的相关突变。结果：免疫组织化学结果判读：细胞阳性率≤ 5% 为1分, 6% ~50% 为2分, 51% ~ 100% 为3分; 染色强度: 不着色为1分, 淡黄色细颗粒状为2分, 黄色颗粒状为3分, 棕黄色粗颗粒状为4分，将两个得分数相乘得到其表达强度。本组7例肾癌骨转移患者VEGFR-2在原发灶(2.86±2.27)和骨转移灶（2.67±1.85）表达差异无统计学意义（P=0.901），而MEK（1.33±0.51 vs. 6.10±4.10,P=0.015）和ERK（4.43±2.84 vs.9.10±2.24, P=0.021）表达差异有统计学意义；在原发灶及转移灶标本中并未检测到相关的基因突变。结论：MEK/ERK通路蛋白在肾癌骨转移患者原发灶和转移灶表达的差异可能与其转移过程有关，也可能是影响靶向治疗效果的原因之一。

Objective： To investigate the expression of MEK/ERK signaling pathways in renal cell carcinoma with bone metastasis, and to analyze the differences of expressions of VEGFR-2, MEK, ERK on the primary and metastasis tissue and its mechanism. Methods: The tissue samples were obtained from 7 renal cell carcinoma patients kindly provided by Department of Urology, Peking University People’s Hospital from January 1, 2009 to January 1, 2010. The expression of MEK/ERK signaling pathways was detected in the 7 renal cell carcinoma patients` primary and matched metastatic tissues with ICH, The antibody concentrations were 1 ∶200, 1 ∶25, and 1 ∶250, respectively. The mutation of the twentieth exon of the PDGFRA gene, the second exon of the K-ras gene, the fifteenth exon of the Braf gene and the se-cond exon of the MEK1 gene were detected with PCR.  Results: The expression intensities of VEGFR-2, MEK, and ERK were measured by H-score ［intensity (1, 2, 3, or 4) multiplied by the distribution (%)］. VEGFR-2, MEK, and ERK expressions were divided into 3 groups according to the positive distribution of the tumor cells: 1, 0－5%; 2, 6%－50%; and 3, >50%, To assess intratumor heterogeneity, three distinct microscopic fields (×200) from each specimen were used to evaluate the expressions, Subsequently, the scores were averaged to obtain a single concatenated score for each tissue. VEGFR-2, MEK, and ERK expressions were assessed by 2 independent pathologists who were blinded to the clinicopathological data. The data were expressed as the mean value of the triplicate experiments. The expressions of MEK, and ERK were higher in the metastatic tissues than in the matched RCC tissues (6.10±4.10 vs.  1.33±0.51, P=0.015; 9.10±2.24 vs. 4.43±2.84, P=0.021) while the expression of VEGFR2 was not different between the primary and metastatic tissues (P=0.901). No mutation was detected on the twentieth exon of the PDGFRA gene, the second exon of the K-ras gene, the fifteenth exon of the Braf gene and the second exon of the MEK1 gene. Conclusion: MEK/ERK signaling pathways may play an important role in the metastasis and the resistance of sunitinib in RCC patients with bone metastasis.