Expression of MEK/ERK signal pathways in renal cell carcinoma with bone metasta-sis / 北京大学学报(医学版)

ABSTRACT

Objective:To investigate the expression of MEK/ERK signaling pathways in renal cell car-cinoma 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 Hos-pital from January 1,2009 to January 1,2010.The expression of MEK/ERK signaling pathways was de-tected in the 7 renal cell carcinoma patients`primary and matched metastatic tissues with ICH,The anti-body 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 Brafgene 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 dis-tribution of the tumor cells1,0 -5%;2,6% -50%;and 3,>50%,To assess intratumor heteroge-neity,three distinct microscopic fields (×200)from each specimen were used to evaluate the expres-sions,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 ex-pression of VEGFR-2 was not different between the primary and metastatic tissues (P =0.901).No mu-tation was detected on the twentieth exon of the PDGFRA gene,the second exon of the K-ras gene,the fifteenth exon of the Brafgene and the second exon of the MEK1 gene.Conclusion:MEK/ERK signa-ling pathways may play an important role in the metastasis and the resistance of sunitinib in RCC patients with bone metastasis.