Molecular markers for predicting prognosis of renal cell carcinoma

Association of Abl interactor 2, ABI2, with platelet/lymphocyte ratio in patients with renal cell carcinoma: A pilot study

There are many unknown aspects of the pathogenesis of renal cell carcinoma (RCC). The aim of the current study was to define new RCC-related genes and measure their associations with RCC and clinical parameters, especially platelet/lymphocyte ratio which may be an independent predictor of prognosis in patients with RCC and other forms of cancer. Via in silico analysis upon RCC-specific deleted genes in chromosome 3, four possible ceRNAs (ATXN3, ABI2, GOLGB1 and SMAD2) were identified. Then, the expression levels of these genes in tumour and adjacent healthy kidney tissues of 19 RCC patients were determined by real-time PCR. ATXN3 and GOLGB1 gene expression levels increased but ABI2 gene expression level decreased in tumour kidney tissues when compared to normal ones. ATXN3, ABI2 and GOLGB1 gene expression levels were significantly higher in Fuhrman grade 4 than other grades (P < .001). ABI2 gene expression levels were significantly associated with higher platelet/lymphocyte ratio of the patients with RCC (P < .05). ATXN3, ABI2 and GOLGB1 may predict higher RCC grades. Also, ABI2 may regulate platelet/lymphocyte ratio which may be an independent predictor of RCC and other forms of cancer.

Cell cycle progression score has potential prognostic value for stage T1 renal cell carcinomas

BACKGROUND

There is an ongoing effort to identify a biomarker which predicts metastatic progression of renal cell carcinoma (RCC).

OBJECTIVE

To evaluate the utility of the cell cycle progression (CCP) score biomarker in predicting metastasis in RCC after local resection of pathologic T1 disease.

DESIGN, SETTING, AND PARTICIPANTS

Pathologic T1 tumors at the University of Iowa were reviewed in patients who had a radical or partial nephrectomy between 1995 and 2010. Patients with known or suspected metastasis, who had received chemotherapy, or who developed metastasis within 60 days of surgery were excluded. Final analysis included 163 patients with RCC who developed metastasis or a new primary within 5 years after surgery or had been followed for 5 years without developing metastasis.

INTERVENTION(S)

Expression levels of 31 cell cycle genes and 15 control genes from the tumor were measured and reported as a CCP score.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The sensitivity, specificity, positive predictive value, and negative predictive value for the development of a metastasis or new primary within 5 years of resection was calculated for varying CCP score cutoffs.

RESULTS AND LIMITATIONS

A total of 4 (2.5%) patients developed metastasis and 7 (4.3%) developed a new primary renal tumor. A CCP score of >-0.25 had a 100% sensitivity and 43% specificity for predicting metastatic progression. A CCP score of >-0.7 had a 100% sensitivity and 20% specificity for predicting the development of a new renal primary.

CONCLUSIONS

The CCP score has potential prognostic value in predicting metastatic progression and might be a useful tool for the management of patients with RCC.

PATIENT SUMMARY

In this study we looked at the utility of a particular gene expression profile from kidney tumors. We found that this gene expression test has the potential to identify tumors at risk of metastasis and thus could be a useful tool in the management of patients with kidney tumors.

Recurrence in Localized Renal Cell Carcinoma: a Systematic Review of Contemporary Data

PURPOSE OF REVIEW

Patients with localized renal cell carcinoma (RCC) are at risk of recurrence. The purpose of this review was to characterize the literature on recurrence rates and risk factors after diagnosis of localized RCC.

RECENT FINDINGS

Our search revealed that existing data examining the prevalence of recurrence rates predominantly originates from cohorts of patients diagnosed and treated in the 1980s to 1990s, and may therefore not be as useful for counseling for current patients today. Many nomograms including the Cindolo Recurrence Risk Formula, the University of California-Los Angeles (UCLA) Integrated Scoring System (UISS), the SSIGN score, the Kattan nomogram, and the Karakiewicz nomogram have shown value in identifying patients at higher risk for recurrence. Biomarkers and gene assays have shown promise in augmenting the predictive accuracy of some of the aforementioned predictive models, especially when multiple gene markers are used in combination. However, more work is needed in not only developing a model but also validating it in other settings prior to clinical use. Adjuvant therapy is a promising new treatment strategy for patients with high-risk disease. Importantly, too many surveillance strategies exist. This may stem from the lack of a consensus in the urological community in how to follow these patients, as well as the variable guideline recommendations. In conclusion, contemporary recurrence rates are needed. Recurrence risk prediction models should be developed based on a series of more contemporary patients, and externally validated prior to routine clinical practice. Surveillance strategies following treatment of localized RCC need to be identified and standardized. Finally, there is a trend toward personalizing surveillance regimens to more appropriately screen patients at higher risk of recurrence.

Renal Cell Carcinoma: A Study through NMR-Based Metabolomics Combined with Transcriptomics

Renal cell carcinoma (RCC) is a heterogeneous cancer often showing late symptoms. Until now, some candidate protein markers have been proposed for its diagnosis. Metabolomics approaches have been applied, predominantly using Mass Spectrometry (MS), while Nuclear Magnetic Resonance (NMR)-based studies remain limited. There is no study about RCC integrating NMR-based metabolomics with transcriptomics. In this work, ¹H-NMR spectroscopy combined with multivariate statistics was applied on urine samples, collected from 40 patients with clear cell RCC (ccRCC) before nephrectomy and 29 healthy controls; nine out of 40 patients also provided samples one-month after nephrectomy. We observed increases of creatine, alanine, lactate and pyruvate, and decreases of hippurate, citrate, and betaine in all ccRCC patients. A network analysis connected most of these metabolites with glomerular injury, renal inflammation and renal necrosis/cell death. Interestingly, intersecting metabolites with transcriptomic data from CD133+/CD24+ tumoral renal stem cells isolated from ccRCC patients, we found that both genes and metabolites differentially regulated in ccRCC patients belonged to HIF-α signaling, methionine and choline degradation, and acetyl-CoA biosynthesis. Moreover, when comparing urinary metabolome of ccRCC patients after nephrectomy, some processes, such as the glomerular injury, renal hypertrophy, renal necrosis/cell death and renal proliferation, were no more represented.

A Molecular Model for Predicting Overall Survival in Patients with Metastatic Clear Cell Renal Carcinoma: Results from CALGB 90206 (Alliance)

BACKGROUND

Prognosis associated with metastatic renal cell carcinoma (mRCC) can vary widely.

METHODS

This study used pretreatment nephrectomy specimens from a randomized phase III trial. Expression levels of candidate genes were determined from archival tumors using the OpenArray® platform for TaqMan® RT-qPCR. The dataset was randomly divided at 2:1 ratio into training (n = 221) and testing (n = 103) sets to develop a multigene prognostic signature.

FINDINGS

Gene expressions were measured in 324 patients. In the training set, multiple models testing 424 candidate genes identified a prognostic signature containing 8 genes plus MSKCC clinical risk factors. In the testing set, the time dependent (td) AUC for a prognostic model containing the 8 genes with and without MSKCC risk factors were 0.72 and 0.69, respectively. The tdAUC for the clinical risk factors alone was 0.61. Additional primary mRCCs from patients with mRCC (n = 12) were sampled in multiple sites and standard deviations of gene expressions within a tumor were used as a measure of heterogeneity. All 8 genes in the final prognostic model met our criteria for minimal heterogeneity.

CONCLUSIONS

A molecular prognostic signature based on 8 genes was developed and is ready for external validation in this patient population and other related settings such as nonmetastatic RCC.

Genomic Analysis as the First Step toward Personalized Treatment in Renal Cell Carcinoma

Drug resistance mechanisms in renal cell carcinoma (RCC) still remain elusive. Although most patients initially respond to targeted therapy, acquired resistance can still develop eventually. Most of the patients suffer from intrinsic (genetic) resistance as well, suggesting that there is substantial need to broaden our knowledge in the field of RCC genetics. As molecular abnormalities occur for various reasons, ranging from single nucleotide polymorphisms to large chromosomal defects, conducting whole-genome association studies using high-throughput techniques seems inevitable. In principle, data obtained via genome-wide research should be continued and performed on a large scale for the purposes of drug development and identification of biological pathways underlying cancerogenesis. Genetic alterations are mostly unique for each histological RCC subtype. According to recently published data, RCC is a highly heterogeneous tumor. In this paper, the authors discuss the following: (1) current state-of-the-art knowledge on the potential biomarkers of RCC subtypes; (2) significant obstacles encountered in the translational research on RCC; and (3) recent molecular findings that may have a crucial impact on future therapeutic approaches.

DHH is an independent prognosticator of oncologic outcome of clear cell renal cell carcinoma

PURPOSE

Aberrant HH signaling has proved important in the pathogenesis of several solid cancers. Limited in vitro analyses suggested an oncogenic role for HH in renal cell carcinoma. In this explorative study we sought to validate aberrant HH expression in patients with renal cell carcinoma.

MATERIALS AND METHODS

A tissue microarray was constructed from 140 radical nephrectomy specimens of patients with clear cell renal cell carcinoma. We performed immunohistochemistry for Ki67 and HH pathway biomarkers, including PTCH1, Smo, SHH, IHH, DHH, Gli1, Gli2 and Gli3. Staining intensity was measured by automated image processing and related to tumor stage and grade. The impact of biomarker expression on cancer specific survival was determined by univariate and multivariate Cox regression analysis.

RESULTS

Gli3, PTCH1, DHH and SHH demonstrated markedly higher expression in high than in low grade tumors. Tumor stage was not associated with marker expression. On univariate analysis DHH expression, and tumor grade and stage were associated with cancer specific survival. Multivariate analysis revealed that DHH, grade and stage were independent predictors of cancer specific survival.

CONCLUSIONS

To our knowledge we report for the first time that a biomarker of the HH pathway is associated with adverse pathological features and poor disease outcomes in patients with clear cell renal cell carcinoma. DHH may serve as an independent predictor of cancer specific survival in clear cell renal cell carcinoma cases. This supports further evaluation of HH signaling to validate the pathway as a target for novel therapy.

The urinary proteome and peptidome of renal cell carcinoma patients: a comparison of different techniques

Renal cell carcinomas, originating from the renal cortex, account for about 80% of kidney primary malignancies. Small localized tumors rarely produce symptoms and diagnosis is often delayed until the disease is advanced. In contrast to other urological cancers, renal cell carcinomas are associated with a high degree of metastases and a low 5-year survival rate. The identification of diagnostic and prognostic markers, especially in the urine, remains an area of intense investigation. Different proteomic strategies have been applied so far to biomarker discovery in urine at the proteome or the peptidome level. Gel-based and gel-free strategies combined with mass spectrometry are the most-used strategies, have different success rates, and will be depicted here. We also prefigure a scenario in which the limitations of a single approach are overcome by applying new and complementary research strategies, relying on the excellent availability coupled to the intrinsic richness typical of urine samples.

Overexpression of cyclooxygenase-1 correlates with poor prognosis in renal cell carcinoma

The aim of this study was to evaluate expression of COX-1 in renal cell carcinoma (RCC) and its prognostic value. mRNA of COX-1 was detected in 42 paired RCC and adjacent normal tissues with quantitative real- time polymerase chain reaction (qRT-PCR). Expression of COX-1 was also evaluated in 196 RCC sections and 91 adjacent normal tissues with immunohistochemistry. Statistical analysis was performed to assess COX-1 expression in RCC and its prognostic significance. The results of qRT-PCR showed mRNA levels of COX-1 in RCC tissues to be significantly higher than that in adjacent normal tissues (p < 0.001). Immunohistochemical assays also revealed COX-1 to be overexpressed in RCC tissues (p < 0.001). Statistical analysis demonstrated high expression of COX-1 was correlated with tumour size (p = 0.002), pathological stage (p = 0.003), TNM stage (p = 0.003, 0.007, 0.027, respectively), and tumour recurrence (p < 0.001). Survival analysis indicated patients with high expression of COX-1 had shorter survival time (p < 0.001), and COX-1 was an independent predictor. This is the first study to reveal overexpression of COX-1 in RRC and point to use as a prognostic marker in affected patients.

The specificity of urinary aquaporin 1 and perilipin 2 to screen for renal cell carcinoma

PURPOSE

Renal cancer is frequently asymptomatic until late stages of the disease and it has a poor prognosis when not discovered early. AQP1 and PLIN2 are recently discovered, sensitive urine biomarkers of clear cell and papillary kidney cancer. We validated these biomarkers in a second cohort of patients and determined the effect of common kidney diseases on specificity.

MATERIALS AND METHODS

Urine samples were obtained from 36 patients with clear cell or papillary kidney cancer, 43 controls, 44 patients with documented urinary tract infection, 24 diagnosed with diabetic nephropathy and 18 diagnosed with glomerulonephritis. Urine levels of AQP1 and PLIN2 normalized to urine creatinine were determined by a sensitive, specific Western blot procedure.

RESULTS

Compared with controls, urine AQP1 and PLIN2 levels in patients with kidney cancer were 23-fold and fourfold greater, respectively, and they decreased 83% to 84% after tumor excision. There was a linear correlation between urine AQP1 and PLIN2 levels, and tumor size (each p <0.001). Urine AQP1 and PLIN2 levels in patients with kidney cancer were 11 to 23-fold and 17 to 25-fold greater, respectively, than in patients with the common kidney diseases.

CONCLUSIONS

The ability of urine AQP1 and PLIN2 to identify patients with kidney cancer compared to controls was validated in a second cohort of patients. Common kidney diseases do not adversely increase urine AQP1 and PLIN2 levels or decrease their specificity to screen for renal cancer.

Proteomic identification of angiomotin by ProteomeLab PF-2D and correlation with clinical outcome in human clear cell renal cell carcinoma

Identification of new therapeutic and prognostic biomarkers for clear cell renal cell carcinoma (ccRCC) is urgently required since most patients are in advanced stages of ccRCC at initial diagnosis and the recurrence rate is high. Differentially expressed proteins between the ccRCC cell line RLC-310 and the normal renal cell line HK-2 were identified by a comparative proteomic approach based on a protein fractionation two-dimensional (PF-2D) liquid-phase fractionation system and capillary liquid chromatography electrospray ionization mass spectrometry/mass spectrometry (LC-ESI-MS/MS). Differentially expressed proteins (n=196) were identified. Of the 13 differentially expressed proteins newly discovered in ccRCC, angiomotin (Amot) was the focus of this study since its role in ccRCC progression has been obscure. The overexpression of Amot in ccRCC tissues was confirmed by comparing Amot expression in 18 primary ccRCC tissues and adjacent normal renal tissues (ANRT) using western blot analysis. Quantitative RT-PCR using 127 ccRCC tissues revealed that high levels of Amot transcripts were associated with poor differentiation, venous invasion and decreased survival (p<0.0001, <0.05 and <0.05). Multivariate analysis indicated that Amot transcript was an independent prognostic factor for the survival of ccRCC patients (p<0.05). These data suggest that Amot may serve as a novel prognostic factor of ccRCC.

Impact of ischemia and procurement conditions on gene expression in renal cell carcinoma

PURPOSE

Previous studies have shown that ischemia alters gene expression in normal and malignant tissues. There are no studies that evaluated effects of ischemia in renal tumors. This study examines the impact of ischemia and tissue procurement conditions on RNA integrity and gene expression in renal cell carcinoma.

EXPERIMENTAL DESIGN

Ten renal tumors were resected without renal hilar clamping from 10 patients with renal clear cell carcinoma. Immediately after tumor resection, a piece of tumor was snap frozen. Remaining tumor samples were stored at 4°C, 22°C, and 37°C and frozen at 5, 30, 60, 120, and 240 minutes. Histopathologic evaluation was conducted on all tissue samples, and only those with greater than 80% tumor were selected for further analysis. RNA integrity was confirmed by electropherograms and quantitated using RNA integrity number index. Altered gene expression was assessed by paired, two-sample t test between the zero time point and aliquots from various conditions obtained from the same tumor.

RESULTS

One hundred and forty microarrays were conducted. Some RNA degradation was observed 240 minutes after resection at 37°C. The expression of more than 4,000 genes was significantly altered by ischemia times or storage conditions. The greatest gene expression changes were observed with longer ischemia time and warmer tissue procurement conditions.

CONCLUSION

RNA from kidney cancer remains intact for up to 4 hours post surgical resection regardless of storage conditions. Despite excellent RNA preservation, time after resection and procurement conditions significantly influence gene expression profiles. Meticulous attention to preacquisition variables is of paramount importance for accurate tumor profiling.

Heparanase expression and glycosaminoglycans profile in renal cell carcinoma

A better understanding of the molecular mechanisms of renal cell carcinogenesis could contribute to a decrease in the mortality rate of this disease. The aim of this study was to evaluate the glycosaminoglycans profile and heparanase expression in renal cell carcinoma. The study included 24 patients submitted to nephrectomy with confirmed pathological diagnosis of renal cell carcinoma. The majority of the samples (87.5%) were classified in the initial stage of renal cell carcinoma (clinical stages I and II). Heparanase messenger ribonucleic acid expression was evaluated by quantitative real-time reverse transcription polymerase chain reaction, and sulfated glycosaminoglycans were identified and quantified by agarose gel electrophoresis of renal cell carcinoma samples or non-neoplastic tissues obtained from the same patients (control group). The sulfated glycosaminoglycans and hyaluronic acid were analyzed in urine samples of the patients before and after surgery. The data showed a significant statistical increase in chondroitin sulfate, and a decrease in heparan sulfate and dermatan sulfate present in neoplastic tissues compared with non-neoplastic tissues. Higher heparanase messenger ribonucleic acid expression in the neoplastic tissues was also shown, compared with the non-neoplastic tissues. The urine glycosaminoglycans profile showed no significant difference between renal cell carcinoma and control samples. Extracellular matrix changes observed in the present study clarify that heparanase is possibly involved with heparan sulfate turnover, and that heparanase and the glycosaminoglycans can modulate initial events of renal cell carcinoma development.

Kinome expression profiling identifies IKBKE as a predictor of overall survival in clear cell renal cell carcinoma patients

There are 516 known kinases in the human genome. Because of their important role maintaining proper cellular function, they are often misregulated during tumorigenesis and associated with clinical outcomes in cancer patients, including clear cell renal cell carcinoma (ccRCC). However, less is known about the global expression status of these genes in renal cell carcinoma and their association with clinical outcomes. We performed a systematic analysis of gene expression for 503 kinases in 93 tumor samples and adjacent normal tissues. Expression patterns for 41 kinases were able to clearly differentiate tumor and normal samples. Expression of I-kappa-B kinase epsilon (IKBKE) was associated with a 5.3-fold increased risk of dying [95% confidence interval (CI): 1.93-14.59, P-value: 0.0012]. Individuals with high IKBKE expression were at a significantly increased risk of death (hazard ratio: 3.34, 95% CI: 1.07-10.40, P-value: 0.038) resulting in a significantly reduced overall survival time compared with those with low IKBKE tumor expression (P-value: 0.049). These results for IKBKE were validated in a replication population consisting of 237 ccRCC patients (P-value: 0.0021). Furthermore, IKBKE was observed to be higher expressed in tumors compared with adjacent normal tissues (P-value < 10(-7)). IKBKE is a member of the nuclear factor-kappaB (NF-κB) signaling pathway and interestingly, gene expression patterns for other members of the NF-κB pathway were not associated with survival, suggesting that IKBKE gene expression may be an independent marker of variation in overall survival. Overall, these results support a novel role for IKBKE expression in modulating overall survival in ccRCC patients.

Sensitivity and specificity of urinary neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 for the diagnosis of renal cell carcinoma

BACKGROUND/AIMS

Neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) are urinary biomarkers of diagnostic relevance in a wide variety of acute and chronic kidney diseases. Their diagnostic sensitivity and specificity for kidney cancer are largely unknown and therefore the subject of this investigation.

METHODS

A prospective cohort study was performed to evaluate urine biomarkers for clear-cell and papillary subtypes of renal cancer (67 patients undergoing nephrectomy) and 55 control patients undergoing non-kidney surgery. Urinary KIM-1 and NGAL concentrations were determined by sensitive and specific ELISAs.

RESULTS

In renal cancer patients, median NGAL excretion was 0.52 (1st to 3rd quartiles: 0.28-0.82) ng/mg urinary creatinine (U(Cr)) before nephrectomy compared to 0.15 (0.04-0.31) ng/mg U(Cr) in controls (p < 0.001), and there was a modest decrease of 30% after nephrectomy (p < 0.008). NGAL was not correlated to tumor size (r = 0.19, p = 0.27) or stage. Before nephrectomy, KIM-1 excretion was 0.68 (0.40-1.12) ng/mg U(Cr) compared to 0.03 (0.01-0.06) in controls (p < 0.001). There was a linear correlation between KIM-1 excretion before nephrectomy and tumor size (Spearman's r = 0.66, p < 0.001), tumor stage, and a 50% decrease in median KIM-1 concentration 1 month following tumor excision (p < 0.01). Biomarker concentration ranges for renal cancer patients and controls overlapped substantially for NGAL but not KIM-1.

CONCLUSION

NGAL is not a sensitive or specific urinary biomarker of kidney cancer. Although KIM-1 had diagnostic sensitivity for kidney cancer, it is well known to reflect many types of kidney injuries, thus limiting its specificity as a diagnostic biomarker for renal cancer.

Basic research in kidney cancer

CONTEXT

Advances in basic research will enhance prognosis, diagnosis, and treatment of renal cancer patients.

OBJECTIVE

To discuss advances in our understanding of the molecular basis of renal cancer, targeted therapies, renal cancer and immunity, and genetic factors and renal cell carcinoma (RCC).

EVIDENCE ACQUISITION

Data on recently published (2005-2011) basic science papers were reviewed.

EVIDENCE SYNTHESIS

Advances in basic research have shown that renal cancers can be subdivided based on specific genetic profiles. Now that this molecular basis has been established, it is becoming clear that additional events play a major role in the development of renal cancer. For example, aberrant chromatin remodelling appears to be a main driving force behind tumour progression in clear cell RCC. A large number of potential biomarkers have emerged using various high-throughput platforms, but adequate biomarkers for RCC are still lacking. To bring the potential biomarkers and biomarker profiles to the clinical arena is a major challenge for the field. The introduction of tyrosine kinase inhibitors (TKIs) for therapy has shifted the interest away from immunologic approaches. Nevertheless, a wealth of evidence supports immunotherapy for RCC. Interestingly, studies are now appearing that suggest a combination of TKI and immunotherapy may be beneficial. Thus far, little attention has been paid to patient-specific differences. With high-throughput methods becoming cheaper and with the advances in sequencing possibilities, this situation is expected to change rapidly.

CONCLUSIONS

Great strides have been made in the understanding of molecular mechanisms of RCC. This has led this field to the enviable position of having a range of molecularly targeted therapies. Large sequencing efforts are now revealing more and more genes responsible for tumour development and progression, offering new targets for therapy. It is foreseen that through integration of high-throughput platforms, personalised cancer treatment for RCC patients will become possible.

A specific gene expression signature characterizes metastatic potential in clear cell renal cell carcinoma

PURPOSE

The discovery of metastasis markers in clear cell renal cell carcinoma is of critical importance to define individual metastatic risk and select patients for new targeted therapies. We identified potential biomarkers for metastatic clear cell renal cell carcinoma by gene expression analysis.

MATERIALS AND METHODS

We performed transcriptional profiling of 16 primary metastatic and 18 nonmetastatic clear cell renal cell carcinomas with PIQOR™ microarrays. Differentially expressed genes were validated by quantitative real-time polymerase chain reaction.

RESULTS

Genes discriminating between metastatic and nonmetastatic tumors were identified at q <0.001 by significance analysis of microarrays. The metastatic signature contained 127 transcripts. In metastatic samples a greater than 4-fold decrease in expression was detected for the genes CD151 and IKBA (t/F statistic p <0.0001) while the genes MMP16, B7-H1, BCL2L2 and FRA2 showed greater than 4-fold increase of expression in metastatic primary tumors (p <0.0001). Quantitative real-time polymerase chain reaction revealed significant differences in expression among all metastatic tumors, including synchronously and metachronously metastasized tumors, and nonmetastatic tumors for FRA2 (p = 0.032) and CD151 (p = 0.005). In addition, the genes B7-H1 (p = 0.040), FRA2 (p = 0.035), CD151 (p = 0.004) and BCL2L2 (p = 0.035) showed significantly higher expression in early metastasized than in nonmetastatic tumor samples. Different B7-H1 (p = 0.002) and BCL2L2 (p = 0.007) expression levels were found in samples with late metastasis compared to those in synchronously metastasized tumors.

CONCLUSIONS

We determined a metastatic signature of clear cell renal cell carcinoma by microarray analysis. Our data provide the possibility of defining the metastatic potential of primary clear cell renal cell carcinoma based on a select number of genes even in a localized situation.

LIM-class homeobox gene Lim1, a novel oncogene in human renal cell carcinoma

Human clear cell renal cell carcinoma (CCC) remains resistant to therapies. The transcription factor LIM-class homeobox gene Lim1 is required for normal organogenesis, including nephrogenesis, by regulating cell movements, differentiation and growth. Its expression is controlled partly by the sonic hedgehog-Gli signaling pathway, which we have recently shown to be reactivated in human CCC. So far, no study has assessed whether Lim1 may be associated with tumorigenesis. Using a panel of human CCC cell lines expressing or not the von Hippel-Lindau tumor suppressor gene and 44 tumor/normal tissues pairs, we found that Lim1 is constitutively and exclusively reexpressed in tumors. Through Lim1 silencing or overexpressing, we show that Lim1 is a growth and survival factor in human CCC, at least through the activation of oncogenic pathways including the phosphoinositide kinase-3/Akt and nuclear factor-kappaB pathways. More importantly, in nude mice bearing human CCC tumors, Lim1 silencing abolished tumor growth through the same mechanism as in vitro. In Lim1-depleted cells and tumors, cell movements were substantially impaired because of the inhibition of expression of various proteins involved in metastatic spread, such as paxillin or tenascin-C. These findings establish that the developmental marker Lim1 acts as an oncogene in cancer cells and targeting Lim1 may constitute an innovative therapeutic intervention in human CCC.

Renal cell carcinoma: where will the state-of-the-art lead us?

Less than 20 years ago, the von Hippel-Lindau (VHL) gene was discovered and associated with sporadic renal cell carcinoma (RCC). Since then, researchers and clinicians have labored to better understand the biology driving RCC tumor progression and provide means to predict patient survival and response to therapy. Studies surrounding VHL inactivation and downstream effects continue to provide insights into these areas. Besides studies of this primary pathway, cytogenetic studies, gene expression analyses, tissue microarrays, serum proteomics, genomic resequencing, and microRNA profiling have yielded greater understanding of RCC biology and clinical presentation, and have led to a rich understanding of the heterogeneity of this disease. We review the current state of research investigations into the molecular biology of RCC, and discuss the applications to currently used clinical prognostic nomograms.

Urinary biomarkers for the early diagnosis of kidney cancer

OBJECTIVE

To test the hypothesis that increased tumor expression of proteins such as aquaporin-1 (AQP1) and adipophilin (ADFP) in patients with renal cancer would result in increased urine AQP1 and ADFP excretion.

PATIENTS AND METHODS

Prenephrectomy and postnephrectomy (pseudocontrol) urine samples were collected from 42 patients with an incidental radiographically discovered renal mass and presurgical presumptive diagnosis of kidney cancer from July 8, 2008, through March 10, 2009. Also enrolled were 15 control patients who underwent nonrenal surgery and 19 healthy volunteers. Urine AQP1 and ADFP concentrations normalized to urine creatinine were determined by sensitive and specific Western blot assays.

RESULTS

Mean +/- SD preexcision urine AQP1 and ADFP concentrations (76+/-29 and 117+/-74 arbitrary units, respectively) in patients with a pathologic diagnosis of clear cell (n=22) or papillary (n=10) cancer were significantly greater than in patients with renal cancer of nonproximal tubule origin, control surgical patients, and healthy volunteers (combined values of 0.1+/-0.1 and 1.0+/-1.6 arbitrary units, respectively; n=44; P<.001). The AQP1 and ADFP concentrations decreased 88% to 97% in the 25 patients with clear cell or papillary cancer who provided postnephrectomy follow-up urine samples. In patients with clear cell and papillary carcinoma, a linear correlation (Spearman) was found between tumor size and preexcision urine AQP1 or ADFP concentration (r=0.82 and 0.76, respectively; P<.001 for each).

CONCLUSION

Urine AQP1 and ADFP concentrations appear to be sensitive and specific biomarkers of kidney cancers of proximal tubule origin. These biomarkers may be useful to diagnose an imaged renal mass and screen for kidney cancer at an early stage.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00851994.

[Prognostic value of erythrocyte polyamines levels in renal cell carcinoma. Prospective study in 418 cases]

OBJECTIVES

Polyamines: Spermine (Spm) and Spermidine (Spmd), are essential for cell proliferation and differentiation. A measurement of erythocytes polyamines (EPA) was developed in our institution. Our objective was to evaluate this marker as a new prognostic factor in renal cell carcinoma.

PATIENTS AND METHODS

A blood sample was prospectively taken before surgery, among 418 patients who had an enlarged nephrectomy (n=318) or a partial nephrectomy (n=100) to quantify EPA rates by using the HPLC technique. The qualitative and quantitative variables have been compared using chi(2) and Student statistical analyses. The survivals have been normalized by the Kaplan Meier and Cox methods.

RESULTS

The average age of our population was 64 years (21-88). The average decline was 41 months (1-214). The median size of tumors was 6.5cm (1-24). The median rate of Spm and Spmd were respectively 4.7 (1-83) and 9 (2-86)nmol/8.10(9) erythrocytes. Spm and Spmd were linked to the T stage (p=0.001), and the ECOG (p=0.001 and 0,008). Spm was not linked at N and M stages but at the Fuhrman grade (p=0.001). Spmd was linked to the N, M stages (p=0.04). With univariate analysis, the tumor diameter, the TNM stage, the Fuhrman grade as well as Spm and Spmd (p<0.0001) were predictors of specific survival. With multivariate analysis, some prognostic factors remained independent: the TNM stage, the ECOG and Spmd, a continuous variable (p=0.0001), pushing the rank of Fuhrman out of the model. When Spm and Spmd were dichotomized in quantitative variables, they were both independent factors.

CONCLUSION

The EPA is a new prognostic tool, before surgery, which will be tested for its integration into prognostic normograms.

Molecular Stratification of Clear Cell Renal Cell Carcinoma by Consensus Clustering Reveals Distinct Subtypes and Survival Patterns

Clear cell renal cell carcinoma (ccRCC) is the predominant RCC subtype, but even within this classification, the natural history is heterogeneous and difficult to predict. A sophisticated understanding of the molecular features most discriminatory for the underlying tumor heterogeneity should be predicated on identifiable and biologically meaningful patterns of gene expression. Gene expression microarray data were analyzed using software that implements iterative unsupervised consensus clustering algorithms to identify the optimal molecular subclasses, without clinical or other classifying information. ConsensusCluster analysis identified two distinct subtypes of ccRCC within the training set, designated clear cell type A (ccA) and B (ccB). Based on the core tumors, or most well-defined arrays, in each subtype, logical analysis of data (LAD) defined a small, highly predictive gene set that could then be used to classify additional tumors individually. The subclasses were corroborated in a validation data set of 177 tumors and analyzed for clinical outcome. Based on individual tumor assignment, tumors designated ccA have markedly improved disease-specific survival compared to ccB (median survival of 8.6 vs 2.0 years, P = 0.002). Analyzed by both univariate and multivariate analysis, the classification schema was independently associated with survival. Using patterns of gene expression based on a defined gene set, ccRCC was classified into two robust subclasses based on inherent molecular features that ultimately correspond to marked differences in clinical outcome. This classification schema thus provides a molecular stratification applicable to individual tumors that has implications to influence treatment decisions, define biological mechanisms involved in ccRCC tumor progression, and direct future drug discovery.

Expression and cytoplasmic localization of SAM68 is a significant and independent prognostic marker for renal cell carcinoma

PURPOSE

This retrospective study aimed to examine the expression and localization of SAM68 (Src-associated in mitosis, 68 kDa) in a larger cohort of surgical specimens of renal cell carcinoma and their correlation with the progression of human renal cell carcinoma.

EXPERIMENTAL DESIGN

The protein and mRNA expression levels of SAM68 in normal renal tubular epithelial cells, renal cell carcinoma cell lines, as well as nine pairs of renal cell carcinoma and matched tumor-adjacent renal tissues were examined using reverse transcription-PCR and Western blot. Moreover, SAM68 protein expression and localization in 241 clinicopathologically characterized renal cell carcinoma samples were examined by immunohistochemistry. Prognostic and diagnostic associations were examined by statistical analyses.

RESULTS

SAM68 was markedly overexpressed in renal cell carcinoma cell lines and renal cell carcinoma tissues at both the transcriptional and translational levels. Immunohistochemical analysis revealed high SAM68 protein expression in 129 of the 241 (53.5%) paraffin-embedded archival renal cell carcinoma specimens. Moreover, there was a significant correlation between SAM68 expression and pathologic stage (P < 0.001), T classification (P = 0.003), N classification (P = 0.001), M classification (P = 0.006), and Fuhrman grade (P < 0.001). Patients with higher SAM68 expression had shorter overall survival time than patients with lower SAM68 expression, and the cytoplasmic localization of SAM68 significantly correlated with clinicopathologic grade and outcome. Multivariate analysis indicated that SAM68 protein overexpression and cytoplasmic localization were independent predictors for poor survival of renal cell carcinoma patients.

CONCLUSIONS

Our results suggest that SAM68 could represent a novel and useful prognostic marker for renal cell carcinoma. High SAM68 expression and cytoplasmic localization are associated with poor overall survival in renal cell carcinoma patients.

Activated extracellular signal-regulated kinase is an independent prognostic factor in clinically confined renal cell carcinoma

BACKGROUND

Extracellular signal-regulated kinase (ERK) promotes proliferation, metastasis, and poor survival in cancers of the breast, lung, and liver. Advanced localized renal cell carcinoma (RCC) is extraordinarily treatment resistant and has high recurrence rates despite surgery. Limited data exist regarding the prognostic significance of activated (phosphorylated) ERK in RCC. The authors hypothesized that activated ERK (pERK) promotes disease progression and metastasis in localized RCC and may be of value as a biomarker to predict disease recurrence.

METHODS

The expression profile of pERK was examined by immunocytochemistry using a tissue microarray constructed from 174 drug treatment-naive patients who had undergone radical nephrectomy for localized RCC. Levels of tumor-cell specific pERK were scored and correlated with clinicopathologic parameters of RCC and disease-free survival.

RESULTS

Immunostaining for pERK was present in 36% of all RCCs, with a predominance found in the clear cell histologic subtype. High expression was associated with increased tumor size, increased TNM stage, and vascular invasion. Patients with pERK-positive tumors had a mean disease-free survival of 4.19 years, compared with 6.38 years for patients with pERK-negative tumors (P<.001). Cox regression models revealed pERK to be a significant independent predictor of disease-free survival, with a hazards score of 2.9 (P<.001), a value similar to tumor grade (hazards ratio, 3.01; P<.001).

CONCLUSIONS

Expression of pERK is an independent prognostic factor in RCC that is associated with advanced and aggressive pathologic features of renal tumors and predicts the onset of metastasis in patients with localized disease.

Predicting disease progression after nephrectomy for localized renal cell carcinoma: the utility of prognostic models and molecular biomarkers

Disease progression after nephrectomy for pathologically localized renal cell carcinoma (RCC) is associated with a significant mortality rate, given the limited efficacy of available treatment regimens for metastatic disease. As such, several adjuvant trials have been designed to treat patients at particularly high risk for postsurgical RCC progression. Several different prognostic models designed to identify patients at high risk of disease progression are available. Although these available predictive models provide a reasonable assessment of patients' risks of disease progression, the accuracy of these models may further be improved via the incorporation of molecular prognostic biomarkers. Although numerous candidate molecules have been described, few have been specifically assessed for the association with disease progression after nephrectomy. IMP-3, CXCR3, p53, Survivin, cIAP1, B7-H1, and B7-H4 have all been associated with disease progression after nephrectomy. The incorporation of 1 or several of these biomarkers may increase the accuracy of currently available prognostic models and thereby facilitate the appropriate use of adjuvant therapies aimed at preventing future disease progression. As such, the authors review the current prognostic tools for predicting disease progression for localized RCC, and detail studies to date that have evaluated various biomarkers in this setting.