The Role Of Protein Tyrosine Phosphatase Receptor Type Delta In Clear Cell Renal Cell Carcinoma Initiation And Progression

Objective:To determine the mRNA and protein expression level of protein tyrosine phosphatase receptor receptor type Delta (PTPRD) gene in clear cell renal cell carcinoma (ccRCC) , and detect D9S168 microsatellite polymorphism and single-nucleotide polymorphisms in PTPRD gene, combined with the prognosis of ccRCC patients, to find one or more biomarkers to screen people susceptibility to ccRCC or vulnerability to poor prognosis of ccRCC, and to make strategies for ccRCC control and prevention be more effective.Methods:Specimens from 93 patients with sporadic ccRCC were used to screen D9S168 microsatellite alterations. Semi-quantitative RT-PCR and Quantitative reverse transcription PCR (qRT-PCR) were used to detect the mRNA transcription level of PTPRD in 32 ccRCC cases, and examined the protein expression level by immunohistochemistry in 65 cases; Polymerase chain reaction restriction fragment length polymorphism (RFLP-PCR) assays were used to analyze the single-nucleotide polymorphisms(SNP) of Rs2279776, Rs34704234 , Rs3215089, Rs2133788,Rs12351899and Rs73398255 in 285 ccRCC cases and 570 healthy controls; The Hardy-Weinberg equilibrium test was performed on the internet (http: //ihg. gsf. de/ihg/snps. html). The SPSS 16.0 was used to analyze the data. Kaplan-Meier method and Cox regression analysis model was used to evaluated the relationship between target factors and the prognosis of ccRCC patients.Results:1, D9S168 alterations (LOH or MSI) occurs in high TNM staging (53.8%), in the 78 patients, whose mean duration of follow-up time was 31.7 months , D9S168 alteration group patients have a poor prognosis (P < 0.001). Cox regression analysis showed that the D9S168 alteration is a independent risk factor for patients died from ccRCC(P =0.009), HR (95% CI) is 17.901 (2.071-154.725).2, According to pathological types, the PTPRD transcription and protein expression level between ccRCC tissues and paired adjacent normal tissues were significant difference(P < 0.05). tumor tissues' PTPRD mRNA transcription level is lower than the adjacent tissues, also tumor tissues' PTPRD protein expression level is lower than the adjacent tissues; PTPRD protein isn't express or lower express in tumor tissues, but mainly express in membrane and parts of cytoplasm of renal proximal tubules' epithelial cell.3, The genotype frequencies distribution of the several genetic polymorphisms in the healthy group, ccRCC group.The genotype frequencies of Rs2279776 CC, CG ,GG in the ccRCC group were 14.0%, 43.5%, and 42.5%, respectively. These frequencies in the control group were 15.3%, 49.8%, and 34.9%, respectively. significant difference was observed between GG group and CC+CG group,the P value is 0.032(P < 0.05), HR (95% CI) is 1.376(1.028-1.841). the polymorphism of Rs34704234, Rs3215098, Rs2133788, Rs12351899 and Rs73398255 were not observed in this research.Conclusion:1, D9S168 microsatellite alteration was independently associated with poor prognosis of ccRCC patients following curative nephrectomy, and can predict a poor prognosis in patients with clear cell Renal Cell Carcinoma.2, D9S168 microsatellite alteration was associated with down-regulation of PTPRD in surgically excised tumor tissues.3, Our immunohistochemical analysis indicated, for the first time, that PTPRD normally expressed in renal tubular epithelial cells, especially in proximal tubular epithelial cells from which ccRCC originated, but not in glomeruli.4, PTPRD is a putative tumor suppressor in ccRCC.5, The SNP rs2279776 (C4396G) is located in exon 27 of the PTPRD gene are associated with the genetic susceptibility of ccRCC, the GG genotype is a pathogenic factor in ccRCC.6, The SNP Rs34704234, Rs3215098, Rs2133788, Rs12351899 and Rs73398255 may be a single genotype in Chinese people.