Clear cell renal cell carcinoma: Gene expression analyses identify a potential signature for tumor aggressiveness
ABSTRACT The objective of this study was to use gene expression profiling to identify novel biomarkers that are predictive of aggressive behavior in clear cell renal cell carcinoma (CCRCC).
Candidate genes were discovered using Human Genome U133 Plus 2 Arrays and validated on independent samples by quantitative reverse transcription-PCR (RT-PCR). Both the discovery and the validation cohorts included nonaggressive primary CCRCC, aggressive primary CCRCC, metastatic CCRCC, and nonneoplastic kidney adjacent to tumor.
Aggressive primary and metastatic CCRCC displayed no significant differences in gene expression. In contrast, we identified significant differences in gene expression between nonaggressive and aggressive CCRCC (including metastatic CCRCC). Thirty-four of the 35 transcripts that displayed the most significant differential expression by microarray analysis also displayed significant differential expression in independent validation studies using quantitative RT-PCR (P < 0.001 for 31 candidates and P < 0.005 for the remaining three candidates). Hierarchical clustering of the quantitative RT-PCR data using our candidate markers accurately grouped 88% (23 of 26) of aggressive and metastatic CCRCC samples, 100% (14 of 14) of nonaggressive CCRCC samples, and 100% (15 of 15) of nonneoplastic samples into separate clusters. Finally, we evaluated the ability of protein expression levels of one of our candidate markers (survivin) to predict survival among a cohort of 183 CCRCC patients treated surgically at Mayo Clinic from 1990 to 1992. In multivariate analysis, expression of survivin (BIRC5) was inversely associated with cancer-specific survival (P = 0.017).
We used a combination of genomic profiling and validation by quantitative PCR to identify a panel of candidate biomarkers for determining CCRCC aggressiveness. Our data also indicate that the gene expression alterations that result in aggressive behavior and metastatic potential can be identified in the primary tumor.
- SourceAvailable from: Charles Swanton
[Show abstract] [Hide abstract]
- "gene expression signatures validated: the aggressive subgroup defined by Kosari  had worse CSS than the nonaggressive subgroup (HR: 2.85; p < 0.001); the Zhao  poor prognosis cluster 2 had worse CSS than cluster 1 (HR: 5.26; p < 0.001). The aggressive subgroup defined by Lane et al.  showed worse CSS than the indolent subgroup (HR: 4.21; p < 0.001); the Brannon  poor prognosis ccB subgroup (HR: 4.90; p < 0.001) had worse CSS than the ccA subgroup. "
ABSTRACT: Background Candidate biomarkers have been identified for clear cell renal cell carcinoma (ccRCC) patients, but most have not been validated. Objective To validate published ccRCC prognostic biomarkers in an independent patient cohort and to assess intratumour heterogeneity (ITH) of the most promising markers to guide biomarker optimisation. Design, setting, and participants Cancer-specific survival (CSS) for each of 28 identified genetic or transcriptomic biomarkers was assessed in 350 ccRCC patients. ITH was interrogated in a multiregion biopsy data set of 10 ccRCCs. Outcome measurements and statistical analysis Biomarker association with CSS was analysed by univariate and multivariate analyses. Results and limitations A total of 17 of 28 biomarkers (TP53 mutations; amplifications of chromosomes 8q, 12, 20q11.21q13.32, and 20 and deletions of 4p, 9p, 9p21.3p24.1, and 22q; low EDNRB and TSPAN7 expression and six gene expression signatures) were validated as predictors of poor CSS in univariate analysis. Tumour stage and the ccB expression signature were the only independent predictors in multivariate analysis. ITH of the ccB signature was identified in 8 of 10 tumours. Several genetic alterations that were significant in univariate analysis were enriched, and chromosomal instability indices were increased in samples expressing the ccB signature. The study may be underpowered to validate low-prevalence biomarkers. Conclusions The ccB signature was the only independent prognostic biomarker. Enrichment of multiple poor prognosis genetic alterations in ccB samples indicated that several events may be required to establish this aggressive phenotype, catalysed in some tumours by chromosomal instability. Multiregion assessment may improve the precision of this biomarker.European Urology 07/2014; 66(5). DOI:10.1016/j.eururo.2014.06.053 · 12.48 Impact Factor
[Show abstract] [Hide abstract]
- "Patients harbouring tumours with methylated APAF1, another apoptotic marker, had a greater risk of recurrence and disease-specific death from RCC  . Increased survivin expression, another inhibitor of apoptosis, has also been independently associated with higher stage and grade and lower disease-specific survival from RCC    . A recent study showed that mTOR activation of pS6K increases protein levels of survivin, which blocks extrinsic and intrinsic apoptotic pathways, showing the role of mTOR in cell survival . "
ABSTRACT: Objectives Increased knowledge about the molecular pathways involved in tumorigenesis has led to the discovery of new prognostic molecular markers and development of novel targeted therapies for renal cell carcinoma (RCC). In this review we describe the prognostic markers of RCC and highlight the areas of recent discovery with a focus on the mammalian target of rapamycin (mTOR) pathway.Methods We reviewed previous reports, using PubMed with the search terms ‘renal cell carcinoma’, ‘molecular markers’, ‘prognosis’, ‘outcomes’ and ‘mammalian target of rapamycin pathway’ published in the last two decades. We created a library of 100 references and focused on presenting the recent advances in the field.ResultsGrowing evidence suggests that mTOR deregulation is associated with many types of human cancer, including RCC. Consequently, temsirolimus and everolimus, which target mTOR, are approved for treating advanced RCC. There is a demand to integrate clinical, pathological and molecular markers into accurate prognostic models to provide patients with the most personalised cancer care possible.Conclusions The mTOR pathway is highly implicated in RCC tumorigenesis and progression, and its constituents might represent a promising prognostic tool and target for treating RCC. Combining newly discovered molecular markers with classic clinicopathological prognostics might potentially improve the management of RCC.Arab Journal of Urology 06/2012; 10(2):110–117. DOI:10.1016/j.aju.2012.02.005
[Show abstract] [Hide abstract]
- "Levels of messenger RNA expression relative to KPNA6 were obtained from a standard curve. We used KPNA6 as a control in this study because KPNA6 expression was not statistically different among the ccRCC and non-neoplastic tissues, although expression levels of known markers such as beta-2-microgloblin and glyceraldehydes 3-phosphate dehydrogenase (GAPDH) were variable across the samples . "
ABSTRACT: Clinical outcome of patients with high-grade ccRCC (clear cell renal cell carcinoma) remains still poor despite recent advances in treatment strategies. Molecular mechanism of pathogenesis in developing high-grade ccRCC must be clarified. In the present study, we found that SAV1 was significantly downregulated with copy number loss in high-grade ccRCCs. Therefore, we investigated the SAV1 function on cell proliferation and apoptosis in vitro. Furthermore, we attempted to clarify the downstream signaling which is regulated by SAV1. We performed array CGH and gene expression analysis of 8 RCC cell lines (786-O, 769-P, KMRC-1, KMRC-2, KMRC-3, KMRC-20, TUHR4TKB, and Caki-2), and expression level of mRNA was confirmed by quantitative RT-PCR (qRT-PCR) analysis. We next re-expressed SAV1 in 786-O cells, and analyzed its colony-forming activity. Then, we transfected siRNAs of SAV1 into the kidney epithelial cell line HK2 and renal proximal tubule epithelial cells (RPTECs), and analyzed their proliferation and apoptosis. Furthermore, the activity of YAP1, which is a downstream molecule of SAV1, was evaluated by western blot analysis, reporter assay and immunohistochemical analysis. We found that SAV1, a component of the Hippo pathway, is frequently downregulated in high-grade ccRCC. SAV1 is located on chromosome 14q22.1, where copy number loss had been observed in 7 of 12 high-grade ccRCCs in our previous study, suggesting that gene copy number loss is responsible for the downregulation of SAV1. Colony-forming activity by 786-O cells, which show homozygous loss of SAV1, was significantly reduced when SAV1 was re-introduced exogenously. Knockdown of SAV1 promoted proliferation of HK2 and RPTEC. Although the phosphorylation level of YAP1 was low in 786-O cells, it was elevated in SAV1-transduced 786-O cells. Furthermore, the transcriptional activity of the YAP1 and TEAD3 complex was inhibited in SAV1-transduced 786-O cells. Immunohistochemistry frequently demonstrated nuclear localization of YAP1 in ccRCC cases with SAV1 downregulation, and it was preferentially detected in high-grade ccRCC. Taken together, downregulation of SAV1 and the consequent YAP1 activation are involved in the pathogenesis of high-grade ccRCC. It is an attractive hypothesis that Hippo signaling could be candidates for new therapeutic target.BMC Cancer 12/2011; 11(1):523. DOI:10.1186/1471-2407-11-523 · 3.32 Impact Factor