Biochemical and molecular markers in renal cell carcinoma: an update and future prospects

The promising potential of piperlongumine as an emerging therapeutics for cancer

In spite of the immense advancement in the diagnostic and treatment modalities, cancer continues to be one of the leading causes of mortality across the globe, responsible for the death of around 10 million patients every year. The foremost challenges faced in the treatment of this disease are chemoresistance, adverse effects of the drugs, and the high cost of treatment. Though scientific studies over the past few decades have foreseen and are focusing on the cancer-preventive and therapeutic potential of natural products and their underlying mechanism of action, many more of these agents are not still explored. Piperlongumine (PL), or piplartine, is one such alkaloid isolated from Piper longum Linn. which is shown to be safe and has significant potential in the prevention and therapy of cancer. Numerous shreds of evidence have established the ability of this alkaloid and its analogs and nanoformulations in modulating various complex molecular pathways such as phosphatidylinositol-3-kinase/protein kinase B /mammalian target of rapamycin, nuclear factor kappa-B, Janus kinases/signal transducer and activator of transcription 3, etc. and inhibit different hallmarks of cancer such as cell survival, proliferation, invasion, angiogenesis, epithelial-mesenchymal-transition, metastases, etc. In addition, PL was also shown to inhibit radioresistance and chemoresistance and sensitize the cancer cells to the standard chemotherapeutic agents. Therefore, this compound has high potential as a drug candidate for the prevention and treatment of different cancers. The current review briefly reiterates the anti-cancer properties of PL against different types of cancer, which permits further investigation by conducting clinical studies.

MITF Promotes Cell Growth, Migration and Invasion in Clear Cell Renal Cell Carcinoma by Activating the RhoA/YAP Signal Pathway

Simple Summary

Microphthalmia-associated transcription factor (MITF) has been reported to play a role in the progression of melanoma and other cancer types. However, the biological role of MITF in clear cell renal cell carcinoma (ccRCC) is largely unknown. In this study, we elucidate the role of MITF in the progression of ccRCC. MITF- and MITF-mediated signaling pathways were investigated in ccRCC cell through MITF knockdown as well as overexpression of MITF in vitro and in vivo. MITF contributed to cell proliferation, migration, invasion and tumor growth in ccRCC through activation of the RhoA/YAP signaling pathways. This study suggests that MITF has potential as a therapeutic target in ccRCC.

Abstract

Microphthalmia-associated transcription factor (MITF) is a basic helix-loop-helix leucine zipper transcription factor involved in the lineage-specific regulation of melanocytes, osteoclasts and mast cells. MITF is also involved in the progression of melanomas and other carcinomas, including the liver, pancreas and lung. However, the role of MITF in clear cell renal cell carcinoma (ccRCC) is largely unknown. This study investigates the functional role of MITF in cancer and the molecular mechanism underlying disease progression in ccRCC. MITF knockdown inhibited cell proliferation and shifted the cell cycle in ccRCC cells. In addition, MITF knockdown reduced wound healing, cell migration and invasion compared with the controls. Conversely, MITF overexpression in SN12C and SNU482 cells increased cell migration and invasion. Overexpression of MITF activated the RhoA/YAP signaling pathway, which regulates cell proliferation and invasion, and increased YAP signaling promoted cell cycle-related protein expression. Additionally, tumor formation was impaired by MITF knockdown and enhanced by MITF overexpression in vivo. In summary, MITF expression was associated with aggressive tumor behavior, and increased the migratory and invasive capabilities of ccRCC cells. These effects were reversed by MITF suppression. These results suggest that MITF is a potential therapeutic target for the treatment of ccRCC.

Androgen receptor (AR) promotes clear cell renal cell carcinoma (ccRCC) migration and invasion via altering the circHIAT1/miR-195-5p/29a-3p/29c-3p/CDC42 signals

Increasing evidence has demonstrated that the androgen receptor (AR) plays important roles to promote the metastasis of clear cell renal cell carcinoma (ccRCC). The detailed mechanisms, especially how AR functions via altering the circular RNAs (circRNAs) remain unclear. Here we identified a new circRNA (named as circHIAT1) whose expression was lower in ccRCCs than adjacent normal tissues. Targeting AR could suppress ccRCC cell progression via increasing circHIAT1 expression. ChIP assay and luciferase assay demonstrated that AR suppressed circHIAT1 expression via regulating its host gene, Hippocampus Abundant Transcript 1 (HIAT1) expression at the transcriptional level. The consequences of AR-suppressed circHIAT1 resulted in deregulating miR-195-5p/29a-3p/29c-3p expressions, which increased CDC42 expression to enhance ccRCC cell migration and invasion. Increasing this newly identified signal via circHIAT1 suppressed AR-enhanced ccRCC cell migration and invasion. Together, these results suggested that circHIAT1 functioned as a metastatic inhibitor to suppress AR-enhanced ccRCC cell migration and invasion. Targeting this newly identified AR-circHIAT1-mediated miR-195-5p/29a-3p/29c-3p/CDC42 signals may help us develop potential new therapies to better suppress ccRCC metastasis.

A decade of pharmacogenomics research on tyrosine kinase inhibitors in metastatic renal cell cancer: a systematic review

OBJECTIVE

The individual response to targeted tyrosine kinase inhibitors (TKIs) in the treatment of metastatic renal cell cancer (mRCC) is highly variable. Outlined in this article are findings on potential biomarkers for TKI treatment outcome in mRCC and an evaluation of the status of clinical implementation.

METHODS

Articles were selected by two independent reviewers using a systematic search in five medical databases on renal cell carcinoma, TKIs, and pharmacogenetics.

RESULTS

Many researchers have focused on predictive biomarkers for treatment outcome of targeted therapies in mRCC patients. Attempts to explain differences in efficacy and toxicity of TKIs by use of genetic variants in genes related to the pharmacokinetics and pharmacodynamics of the drug have been successful.

CONCLUSION

Most findings on potential biomarkers have not been validated and therefore biomarker testing to guide choice of therapy and dose in mRCC is not yet feasible.

Expression pattern of autophagy-related markers in non-metastatic clear cell renal cell carcinoma: association with disease recurrence following radical nephrectomy

PURPOSE

To evaluate the expression of multiple molecular markers associated with autophagy, a cellular degradation pathway for the clearance of damaged or superfluous proteins and organelles, in clear cell renal cell carcinoma (CCRCC) in order to identify the prognostic significance of these markers in patients undergoing radical nephrectomy.

METHODS

Expression levels of five markers, including autophagy-related gene 5 (Atg5), Atg9, Beclin 1, microtubule-associated protein light chain 3 (LC3), and UNC-51-like kinase 1 (ULK1), in radical nephrectomy specimens from a total of 100 patients with non-metastatic CCRCC were measured by immunohistochemical staining.

RESULTS

All the five markers were significantly correlated with some pathological factors reflecting an aggressive phenotype, including the pathological T stage, tumor grade, and microvascular invasion. During the follow-up period of this series (median 58.0 months), disease recurrence developed in 41 of the 100 patients, with a 5-year recurrence-free survival (RFS) rate of 61.3%. On univariate analysis, expression levels of Atg5 and Beclin 1, in addition to the pathological T stage, microvascular invasion, and preoperative CRP level, were identified as significant predictors of disease recurrence. Of these factors, the expression of Beclin 1 and preoperative CRP level were independently correlated with RFS on multivariate analysis.

CONCLUSION

These findings suggest that the combined assessment of expression levels of autophagy-associated markers, particularly Beclin 1, in radical nephrectomy specimens with conventional prognostic parameters, would contribute to the precise prediction of postoperative disease recurrence in patients with non-metastatic CCRCC.

Infiltrating neutrophils promote renal cell carcinoma (RCC) proliferation via modulating androgen receptor (AR) → c-Myc signals

Early studies found critical roles for neutrophils in renal cell carcinoma (RCC) progression. However, detailed mechanisms of how infiltrating neutrophils in the kidney tumor microenvironment impact RCC progression remain unclear. Here we found more neutrophils were infiltrated in human RCC lesions than those found in surrounding normal kidney tissues. Similarly, in vitro studies also revealed that RCC cells recruited more neutrophil HL-60N cells than normal kidney epithelial cells. Furthermore, in vitro and in vivo experiments also showed that the infiltrated neutrophils could promote RCC cell growth. Mechanism studies showed that co-culture of RCC cells with neutrophil HL-60N cells could selectively upregulate the androgen receptor (AR) signals, which might then alter the c-Myc signals. Interruption approaches using AR-siRNA to knock down AR in RCC cells blocked neutrophil-enhanced RCC cell proliferation. In vivo data using an orthotopically xenografted RCC mouse model also confirmed that infiltrated neutrophils could promote RCC proliferation via modulating the expressions of related cytokines. Together, these results conclude that infiltrated neutrophils may function through modulating the AR → c-Myc signals to promote RCC cell proliferation. Targeting this newly identified infiltrating neutrophil → AR → c-Myc signal pathway in the kidney tumor microenvironment may provide a new potential therapy to better suppress RCC progression.

Analysis and interpretation of transcriptomic data obtained from extended Warburg effect genes in patients with clear cell renal cell carcinoma

Background

Many cancers adopt a metabolism that is characterized by the well-known Warburg effect (aerobic glycolysis). Recently, numerous attempts have been made to treat cancer by targeting one or more gene products involved in this pathway without notable success. This work outlines a transcriptomic approach to identify genes that are highly perturbed in clear cell renal cell carcinoma (CCRCC).

Methods

We developed a model of the extended Warburg effect and outlined the model using Cytoscape. Following this, gene expression fold changes (FCs) for tumor and adjacent normal tissue from patients with CCRCC (GSE6344) were mapped on to the network. Gene expression values with FCs of greater than two were considered as potential targets for treatment of CCRCC.

Results

The Cytoscape network includes glycolysis, gluconeogenesis, the pentose phosphate pathway (PPP), the TCA cycle, the serine/glycine pathway, and partial glutaminolysis and fatty acid synthesis pathways. Gene expression FCs for nine of the 10 CCRCC patients in the GSE6344 data set were consistent with a shift to aerobic glycolysis. Genes involved in glycolysis and the synthesis and transport of lactate were over-expressed, as was the gene that codes for the kinase that inhibits the conversion of pyruvate to acetyl-CoA. Interestingly, genes that code for unique proteins involved in gluconeogenesis were strongly under-expressed as was also the case for the serine/glycine pathway. These latter two results suggest that the role attributed to the M2 isoform of pyruvate kinase (PKM2), frequently the principal isoform of PK present in cancer: i.e. causing a buildup of glucose metabolites that are shunted into branch pathways for synthesis of key biomolecules, may not be operative in CCRCC. The fact that there was no increase in the expression FC of any gene in the PPP is consistent with this hypothesis. Literature protein data generally support the transcriptomic findings.

Conclusions

A number of key genes have been identified that could serve as valid targets for anti-cancer pharmaceutical agents. Genes that are highly over-expressed include ENO2, HK2, PFKP, SLC2A3, PDK1, and SLC16A1. Genes that are highly under-expressed include ALDOB, PKLR, PFKFB2, G6PC, PCK1, FBP1, PC, and SUCLG1.

Active angiogenesis in metastatic renal cell carcinoma predicts clinical benefit to sunitinib-based therapy

Background:

Sunitinib represents a widely used therapy for metastatic renal cell carcinoma patients. Even so, there is a group of patients who show toxicity without clinical benefit. In this work, we have analysed pivotal molecular targets involved in angiogenesis (vascular endothelial growth factor (VEGF)-A, VEGF receptor 2 (KDR), phosphorylated (p)KDR and microvascular density (MVD)) to test their potential value as predictive biomarkers of clinical benefit in sunitinib-treated renal cell carcinoma patients.

Methods:

Vascular endothelial growth factor-A, KDR and pKDR-Y1775 expression as well as CD31, for MVD visualisation, were determined by immunohistochemistry in 48 renal cell carcinoma patients, including 23 metastatic cases treated with sunitinib. Threshold was defined for each biomarker, and univariate and multivariate analyses for progression-free survival (PFS) and overall survival (OS) were carried out.

Results:

The HistoScore mean value obtained for VEGF-A was 121.6 (range, 10–300); for KDR 258.5 (range, 150–300); for pKDR-Y1775 10.8 (range, 0–65) and the mean value of CD31-positive structures for MVD visualisation was 49 (range, 10–126). Statistical differences for PFS (P=0.01) and OS (P=0.007) were observed for pKDR-Y1775 in sunitinib-treated patients. Importantly, pKDR-Y1775 expression remained significant after multivariate Cox analysis for PFS (P=0.01; HR: 5.35, 95% CI, 1.49–19.13) and for OS (P=0.02; HR: 5.13, 95% CI, 1.25–21.05).

Conclusions:

Our results suggest that the expression of phosphorylated (i.e., activated) KDR in tumour stroma might be used as predictive biomarker for the clinical outcome in renal cell carcinoma first-line sunitinib-treated patients.

Serum N-glycan alteration associated with renal cell carcinoma detected by high throughput glycan analysis

PURPOSE

Biomarkers for the early detection and prediction of survival in patients with renal cell carcinoma have not been established. We developed what is to our knowledge a novel glycoblotting method that allows high throughput, comprehensive, quantitative analysis of glycans in human serum. In this study we identified alterations in serum N-glycans associated with renal cell carcinoma.

MATERIALS AND METHODS

We performed a comprehensive N-glycan structural analysis of serum from 64 patients with renal cell carcinoma and 34 age matched, healthy volunteers using glycoblotting methods and matrix-assisted laser desorption/ionization-time of flight mass spectrometry. The peak intensity of N-glycan was analyzed using logistic regression analysis and ROCs were used to select candidate N-glycans. Candidate N-glycans with a statistically significant relationship to renal cell carcinoma or overall survival were independently evaluated using a Cox regression model to determine superiority compared to other conventional renal cell carcinoma biomarkers.

RESULTS

We identified 56 types of N-glycans in serum from healthy volunteers and patients with renal cell carcinoma. Peaks 40 and 43 were significantly more intense in patients than in volunteers. Peak 19 intensity was significantly higher and peak 49 intensity was significantly lower in patients with renal cell carcinoma who survived for a longer period. Multivariate analysis revealed that peaks 19 and 49 were independent predictors of overall survival.

CONCLUSIONS

Serum N-glycan analysis is a promising approach to discovering new biomarkers for renal cell carcinoma. Further study is warranted to validate our results.

Evaluation of neutrophil gelatinase-associated lipocalin (NGAL), matrix metalloproteinase-9 (MMP-9) and their complex MMP-9/NGAL in sera and urine of patients with kidney tumors

Recent evidence suggests that neutrophil gelatinase-associated lipocalin (NGAL) is required for the development and/or progression of benign and malignant disease, and is overexpressed in several types of tumor. Matrix metalloproteinase-9 (MMP-9), by degrading components of the extracellular matrix and thus promoting the release of growth factors, is important in tumor growth and tumorigenicity. NGAL protects MMP-9 from proteolytic degradation and enhances its enzymatic activities by binding and forming the MMP-9/NGAL complex. Therefore, NGAL, MMP-9 and their complex MMP-9/NGAL have been proposed as soluble biomarkers for numerous malignancies. In the present study, we measured the concentration of these molecules in sera and urine of patients with kidney disease using ELISA. Of these patients, 16 had clear cell renal cell carcinoma (ccRCC) and 4 had oncocytoma. Sera and urine samples of 53 healthy patients were used as controls. In sera, MMP-9 was enhanced in ccRCC patients compared with oncocytoma patients. In urine, the most abundant molecule was NGAL and its mean value was higher in cancer patients. However, there was a broad overlap of the data and we did not identify any correlation with disease type, stage or grade. Therefore, these molecules may not be useful as biomarkers for predicting kidney carcinoma.

Down-regulation of CD74 inhibits growth and invasion in clear cell renal cell carcinoma through HIF-1α pathway

OBJECTIVES

To investigate the expression and function of CD74 in normal renal tissue and clear cell-renal cell carcinoma (ccRCC), as well as related renal tubule epithelial lines. We also analyzed the association between clinicopathological characteristics of ccRCCs and the expression levels of CD74.

METHODS

Immunostaining of CD74 was performed in 107 patients' renal tissue and cell lines. We evaluated the association between clinicopathological characteristics of ccRCC and CD74 levels using image analysis. CD74 expression levels were also analyzed by Western blot. Lentivirus-mediated CD74 knockdown inhibited the growth and invasion, of ccRCC cell lines 786-O in vitro and in vivo. Cell proliferation, apoptosis, and invasion as well as HIF-1α pathway-related proteins, were estimated by Western blot. All experiments were repeated at least 3 times.

RESULTS

Immunostaining and image analysis showed strong immunoreactions of CD74 in all patients' ccRCC tissue and malignant cell lines, while CD74 expression levels were associated with tumor grade (P = 0.013). Western blot indicated that ccRCC tissue and malignant cell lines expressed higher levels of CD74 and hypoxia inducible factor 1α (HIF-1α) than adjacent normal renal tissue and normal cell HK-2. Vitro and vivo tests demonstrated that lentivirus-mediated CD74 knockdown inhibited the proliferation of ccRCC cell lines, induced G1/S arrest and apoptosis, and inhibited invasion. Inhibition of CD74 resulted in down-regulation of HIF-1α pathway proteins.

CONCLUSIONS

CD74 was overexpressed in human ccRCCs and associated with tumor grade, and inhibition of CD74 produced ccRCC proliferation arrest, induced apoptosis, and inhibited invasion, which impinged on HIF-1α pathway-related proteins. It might represent a potential therapeutic target for ccRCC.

Matrix metalloproteinase-2 and -9 in the sera and in the urine of human oncocytoma and renal cell carcinoma

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases, capable of degrading all the molecular components of extracellular matrix. MMPs have been shown to play critical roles in tumor cell invasion and metastasis. We verified the activity of MMPs in the sera and in the urine of patients with kidney carcinoma by gelatin zymography. Of these patients, 16 had clear cell renal carcinoma (ccRCC) and 4 patients had oncocytoma. The sera and the urine of 16 healthy subjects were used as controls. In the sera, zymography analysis showed gelatinolytic bands at 72 kDa (gelatinase A) at 92, 130 and 240 kDa (gelatinase B). MMP-9 activity was slightly enhanced in sera from ccRCC compared with oncocytoma patients. Serum MMP-2 activity was similar in ccRCC and in oncocytoma patients. In the urine, 2 oncocytoma patients and 3 (33%) of the ccRCC patients showed gelatinolytic activity, whereas MMPs could not be detected in the concentrated urine of healthy subjects. The most abundant lytic activity was at 92 kDa, whereas MMP-2 was present in lesser quantities. However, there was broad overlap of the data and we did not find any correlation to type, stage or grade. Therefore, despite previous evidence, MMP-2 and -9 activity in serum and urine may not be useful biomarker for kidney carcinomas.

Role of VHL gene mutation in human renal cell carcinoma

The Von Hippel-Lindau (VHL) is an inherited neoplasia syndrome caused by the inactivation of VHL tumor suppressor gene, and somatic mutation of this gene has been related to the development of sporadic clear cell renal carcinoma. The affected individuals are at higher risk for the development of tumor in other organs, which include pheochromocytomas, retinal angioma, pancreatic cysts, and CNS hemangioblastomas. The VHL mRNA encodes a protein (pVHL) that contains 213 amino acid residues which migrate with an apparent molecular weight of 24 to 30 kDa. The VHL gene protein has multiple functions that are linked to tumor suppression, but the best recognized and evidently linked to the development of renal cell carcinoma (RCC) is inhibition of hypoxia-inducible factor (HIF), as well as plays a role in targeting HIF for ubiquitin-mediated degradation. Aberrations in VHL's function, either through mutation or promoter hypermethylation, lead to the accumulation of HIF, which will transcriptionally upregulate a sequence of hypoxia responsive genes, including epidermal growth factor, vascular endothelial growth factor, platelet-derived growth factor, and other proangiogenic factors, resulting in upregulated blood vessel growth, one of the prerequisites of a tumor. HIF plays a critical role in pVHL-defective tumor formation, raising the possibility that drugs directed against HIF or its downstream targets (such as vascular endothelial growth factor) may one day play a role in the treatment of RCC. Moreover, a number of drugs have been developed that target HIF-responsive gene products, many of these targeted therapies have demonstrated significant activity in kidney cancer clinical trials and signify substantive advances in the treatment of this disease.

In search of a better crystal ball: recent advances in prognostic markers for clear-cell renal cell carcinoma

Advances in imaging have led to a steady increase in the incidence of kidney cancer over the last two decades. There has been no corresponding improvement in our ability to predict the behavior of renal cell carcinoma. Patients with low-risk renal cell carcinoma have good long-term survival with only localized therapy but patients with aggressive disease do poorly, even with optimal multimodal treatment. Biomarkers to differentiate between these two very divergent populations have traditionally been of only limited utility. We review the recent advances in the development of molecular and immunologic markers aimed at improving prognostication of renal cell carcinoma.

Prognostic value of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and TRAIL receptors in renal cell cancer

PURPOSE

The death ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and its receptors (TRAIL-R) are involved in immune surveillance and tumor development. Here, we studied a possible association between the expression of TRAIL/TRAIL-Rs and the prognosis in patients with renal cell carcinomas (RCC).

EXPERIMENTAL DESIGN

A tissue microarray containing RCC tumor tissue samples and corresponding normal tissue samples from 838 patients was generated. Expression of TRAIL and TRAIL-Rs was examined by immunohistochemistry and the effect of TRAIL and TRAIL-R expression on disease-specific survival was assessed.

RESULTS

High TRAIL-R2 expression levels were associated with high-grade RCCs (P < 0.001) and correlated negatively with disease-specific survival (P = 0.01). Similarly, high TRAIL expression was associated with a shorter disease-specific survival (P = 0.01). In contrast, low TRAIL-R4 expression was associated with high-stage RCCs (P < 0.001) as well as with the incidence of distant metastasis (P = 0.03) and correlated negatively with disease-specific survival (P = 0.02). In patients without distant metastasis, multivariate Cox regression analyses revealed that TRAIL-R2 and TRAIL are independent prognostic factors for cancer-specific survival (in addition to tumor extent, regional lymph node metastasis, grade of malignancy, and type of surgery).

CONCLUSION

High TRAIL-R2, high TRAIL, and low TRAIL-R4 expression levels are associated with a worse disease-specific survival in patients with RCCs. Therefore, the assessment of TRAIL/TRAIL-R expression offers valuable prognostic information that could be used to select patients for adjuvant therapy studies. Moreover, our findings are of relevance for a potential experimental therapeutic administration of TRAIL-R agonists in patients with RCCs.

Recent advances in neuroblastoma

PURPOSE OF REVIEW

Although there have been recent advances with multimodal therapy, treatment of neuroblastoma remains a clinical challenge. Despite the identification of several genetic features, there has not been a significant increase in 5-year survival in the last decade. This review will highlight the current operative strategies along with new research developments aimed at improving survival.

RECENT FINDINGS

The goal of surgical intervention in the early stages of neuroblastoma is complete curative resection. In advanced-stage disease, tissue biopsy for staging is the initial goal. In recent years, minimally invasive surgery (MIS) is considered in carefully selected patients. Recent advances in neuroblastoma research have focused on tyrosine kinase inhibition, differentiation, pathway inhibition, and immunotherapy. Several of these targets have shown promising results in vivo and are currently under investigation for potential clinical trials.

SUMMARY

New information on the importance of cell signaling and the targeting of specific genes of interest are providing key insights into neuroblastoma. Only through the discovery of novel treatment strategies made available through the advancement of research will neuroblastoma be survivable for patients with advanced-stage disease.

Predictors of survival of advanced renal cell carcinoma: long-term results from Southwest Oncology Group Trial S8949

PURPOSE

S8949 demonstrated improved overall survival for debulking nephrectomy in interferon treated patients with advanced renal cell carcinoma. We present an updated analysis of S8949, now with a median followup of 9 years. We explored clinical predictors of overall survival.

MATERIALS AND METHODS

Univariate and multivariate Cox regression analysis was performed to evaluate the impact of clinical variables potentially influencing survival.

RESULTS

Of 246 patients 241 were eligible and randomized to interferon with or without nephrectomy. Patients randomized to nephrectomy continued to have improved overall survival (HR 0.74, 95% CI 0.57-0.96, p = 0.022). Multivariate analysis showed that performance status 1 vs 0 (HR 1.95, p <0.0001), high alkaline phosphatase (HR 1.5, p = 0.002) and lung metastasis only (HR 0.73, p = 0.028) were overall survival predictors. There was no evidence of an interaction of performance status, measurable disease or lung metastases with nephrectomy (each p >0.30). In a patient subset that survived at least 90 days after randomization early progressive disease within 90 days was prognostic of overall survival in a multivariate model (HR 2.1, p <0.0001), as was performance status (HR 1.7, p = 0.0006).

CONCLUSIONS

Nephrectomy prolonged long-term overall survival in this updated analysis, supporting its role as standard therapy in patients with advanced renal cell carcinoma. A nephrectomy benefit was seen across all prespecified patient subsets. Early progressive disease and performance status were strong predictors of overall survival. These results support efforts to identify biomarkers of renal cell carcinoma resistance to treatment and early progressive disease to facilitate rational patient selection for systemic therapy.

Decoy receptor 3 is a prognostic factor in renal cell cancer

BACKGROUND

Decoy receptor 3 (DcR3) is a soluble protein that binds to and inactivates the death ligand CD95L. Here, we studied a possible association between DcR3 expression and prognosis in patients with renal cell carcinomas (RCCs).

METHODS

A tissue microarray containing RCC tumor tissue samples and corresponding normal tissue samples was generated. Decoy receptor 3 expression in tumors of 560 patients was examined by immunohistochemistry. The effect of DcR3 expression on disease-specific survival and progression-free survival was assessed using univariate analysis and multivariate Cox regression analysis. Decoy receptor 3 serum levels were determined by ELISA.

FINDINGS

High DcR3 expression was associated with high-grade (P = .005) and high-stage (P = .048) RCCs. The incidence of distant metastasis (P = .03) and lymph node metastasis (P = .002) was significantly higher in the group with high DcR3 expression. Decoy receptor 3 expression correlated negatively with disease-specific survival (P < .001) and progression-free survival (P < .001) in univariate analyses. A multivariate Cox regression analysis retained DcR3 expression as an independent prognostic factor that outperformed the Karnofsky performance status. In patients with high-stage RCCs expressing DcR3, the 2-year survival probability was 25%, whereas in patients with DcR3-negative tumors, the survival probability was 65% (P < .001). Moreover, DcR3 serum levels were significantly higher in patients with high-stage localized disease (P = .007) and metastatic disease (P = .001).

INTERPRETATION

DcR3 expression is an independent prognostic factor of RCC progression and mortality. Therefore, the assessment of DcR3 expression levels offers valuable prognostic information that could be used to select patients for adjuvant therapy studies.

Plasma matrix metalloproteinase-7 as a metastatic marker and survival predictor in patients with renal cell carcinomas

We evaluated the clinical usefulness of plasma matrix metalloproteinase-7 (MMP-7) as a diagnostic and prognostic biomarker in patients with renal cell carcinoma (RCC). MMP-7 was quantified in plasma of 50 healthy subjects and 97 RCC patients using a Fluorokine MultiAnalyte Profiling assay. RCC patients were stratified into the following groups: without metastases (N0M0; n = 39), with lymph nodes (N1M0; n = 13), and with distant metastases (M1; n = 45). Diagnostic performance of MMP-7 was analyzed by the receiver operating characteristics (ROC) curve. Kaplan-Meier analysis and the Cox regression model were used to estimate the impact of MMP-7 on the cancer-specific survival outcome of RCC patients. MMP-7 was significantly higher in both metastatic groups N1M0 and M1 (medians, 3.82 and 3.34 microg/L) compared to N0M0 group or controls (medians, 1.85 and 1.64 microg/L; all P < 0.001). In ROC analysis, the area under the ROC curve of MMP-7 was 0.80 in the detection of metastases in RCC (P < 0.0001). In the Kaplan-Meier analysis, patients with MMP-7 above the 95th percentile of controls showed less favorable survival rates compared to those with normal MMP-7 (log-rank test, 15.7; P < 0.0001). High MMP-7 was associated with cancer-related mortality estimated by univariate Cox regression (risk ratio, 4.34, 95% CI, 1.12-10.6; P = 0.032). The multivariate Cox regression model determined MMP-7 (risk ratio, 2.70, 95% CI, 1.39-5.24; P = 0.003) and metastases (risk ratio, 5.81, 95% CI, 2.77-12.2; P < 0.0001) as independent determinants of cancer-related survival outcomes. In conclusion, increased plasma MMP-7 could be related to metastatic disease and poor prognosis in patients with RCC.

Diagnostic and prognostic molecular markers in renal cell carcinoma

PURPOSE

We reviewed the contemporary literature on molecular biomarkers in renal cell carcinoma and their prognostic significance.

MATERIALS AND METHODS

Articles published during 1981 to 2007 in English on renal cell carcinoma were surveyed using the MEDLINE/PubMed database. The subject headings included were genetics, biomarkers, prognosis and risk models of renal cell carcinoma. We present a synthesis of currently known renal cell carcinoma biomarkers at various stages of development and their clinical significance, and prognostic nomograms incorporating biomarkers.

RESULTS

The beneficiary role of biomarkers in renal cell carcinoma is challenged by the relatively low prevalence of the disease. Even if a biomarker for renal cell carcinoma had 100% sensitivity and 99.4% specificity, the positive predictive value of the marker in men older than 65 years would be only 10%. Several biomarkers are being investigated in renal cell carcinoma, of which many relate to pathogenic molecular changes that are currently therapeutic targets. Carbonic anhydrase IX is a von Hippel-Lindau mediated enzyme that is expressed in most renal cell carcinoma cases. High (greater than 85%) expression of this marker indicates favorable prognosis and may predict the response to interleukin-2 therapy. B7-H1 expression in renal cell carcinoma cells/lymphocytes may indicate worse survival, possibly through impaired host antitumor immunity. Prognostic nomograms incorporating clinical variables and molecular markers to refine the prediction of treatment outcomes are in active development and await prospective clinical validation.

CONCLUSIONS

Several renal cell carcinoma molecular markers appear promising to refine the prognosis and prediction of localized, advanced or metastatic renal cell carcinoma. Currently carbonic anhydrase IX is the best studied and promising marker. Prospective, multicenter clinical validation aimed at the practical clinical usefulness of renal cell carcinoma biomarkers is warranted.

Wnt antagonist family genes as biomarkers for diagnosis, staging, and prognosis of renal cell carcinoma using tumor and serum DNA

PURPOSE

We hypothesized that combined methylation analysis of Wnt antagonist genes could serve as a panel of biomarkers for diagnosis, staging, and prognosis in renal cell carcinoma (RCC).

EXPERIMENTAL DESIGN

Samples (n = 62) of RCC and corresponding normal renal tissue (NRT) were analyzed using methylation-specific PCR for methylation of six Wnt antagonist genes (sFRP-1, sFRP-2, sFRP-4, sFRP-5, Wif-1, and Dkk-3). To increase the sensitivity/specificity of RCC detection, the methylation score (M score) for multigene methylation analysis was developed. Receiver operator characteristic curve analysis was used to determine the optimal sensitivity/specificity of the M score. In addition, the M score was compared with the clinicopathologic outcome. Thirty-three serum DNA samples were also used to investigate the methylation status of Wnt antagonist genes.

RESULTS

The methylation levels of all Wnt antagonists were significantly higher in RCC than in NRT. In multivariate regression analysis, the methylation level of sFRP-1 was a significant independent predictor of RCC, whereas for sFRP-2 and sFRP-4 there was a trend toward significance as independent predictors. The M score of Wnt antagonist genes was significantly higher in RCC than in NRT. Overall, the M score had a sensitivity of 79.0% and a specificity of 75.8% (area under the curve, 0.808) as a diagnostic biomarker. In addition, the M score could significantly distinguish grade, pT category, M category, and overall survival of RCC patients. The M score was independent of age and gender in predicting overall survival by the Cox proportional hazards model. In RCC patients, 72.7% of the methylation-specific PCR results had identical methylation in samples of tumor and serum DNA. No serum DNA in normal controls showed aberrant methylation of the Wnt antagonist genes. In addition, the methylation status of Wnt antagonist genes in serum DNA was significantly correlated with tumor grade and stage.

CONCLUSIONS

This is the first report showing that M score analysis of Wnt antagonist genes can serve as an excellent epigenetic biomarker panel for detection, staging, and prognosis of RCC using serum DNA.

In search of suitable reference genes for gene expression studies of human renal cell carcinoma by real-time PCR

Background

Housekeeping genes are commonly used as endogenous reference genes for the relative quantification of target genes in gene expression studies. No conclusive systematic study comparing the suitability of different candidate reference genes in clear cell renal cell carcinoma has been published to date. To remedy this situation, 10 housekeeping genes for normalizing purposes of RT-PCR measurements already recommended in various studies were examined with regard to their usefulness as reference genes.

Results

The expression of the potential reference genes was examined in matched malignant and non-malignant tissue specimens from 25 patients with clear cell renal cell carcinoma. Quality assessment of isolated RNA performed with a 2100 Agilent Bioanalyzer showed a mean RNA integrity number of 8.7 for all samples. The between-run variations related to the crossing points of PCR reactions of a control material ranged from 0.17% to 0.38%. The expression of all genes did not depend on age, sex, and tumour stage. Except the genes TATA box binding protein (TBP) and peptidylprolyl isomerase A (PPIA), all genes showed significant differences in expression between malignant and non-malignant pairs. The expression stability of the candidate reference genes was additionally controlled using the software programs geNorm and NormFinder. TBP and PPIA were validated as suitable reference genes by normalizing the target gene ADAM9 using these two most stably expressed genes in comparison with up- and down-regulated housekeeping genes of the panel.

Conclusion

Our study demonstrated the suitability of the two housekeeping genes PPIA and TBP as endogenous reference genes when comparing malignant tissue samples with adjacent normal tissue samples from clear cell renal cell carcinoma. Both genes are recommended as reference genes for relative gene quantification in gene profiling studies either as single gene or preferably in combination.

Elevated plasma osteopontin as marker for distant metastases and poor survival in patients with renal cell carcinoma

PURPOSE

To evaluate diagnostic and prognostic significance of plasma osteopontin (OPN) in patients with renal cell carcinoma (RCC).

METHODS

The retrospective study included 80 patients with RCC (pN0M0, n = 32; pN1M0, n = 11; M1, and n = 37), and 52 healthy controls (27 females and 25 males). OPN, the bone marker bone-specific alkaline phosphatase (bALP) and carboxyterminal telopetide of type-I collagen (ICTP), and the enzymes alanine aminotransferase (ALAT), and gamma-glutamyltransferase (GGT) were evaluated together with Memorial Sloan-Kettering Cancer Center (MSKCC) laboratory parameters. Data were analyzed by receiver-operating characteristics (ROC), survival analysis, and Cox proportional hazards regression model.

RESULTS

OPN and ICTP levels in RCC patients with distant metastases were significantly elevated (medians 115 and 4.7 microg/l, P < 0.001) compared to those without metastases (31.1 and 2.5 microg/l) and controls (28.9 and 2.1 microg/l) but did not differ between patients with bone or non-bone metastases. Both bALP and ALAT were not different between all study groups, while GGT was only increased in patients with non-bone metastases. In ROC analysis, OPN showed the best discrimination between patients with and without metastases (area under the curve: 0.888). High OPN values were associated with poor survival (Kaplan-Meier analysis, log-rank test, P = 0.002). Multivariate Cox regression with forward and backward stepwise elimination confirmed plasma OPN as independent predictive survival factor in RCC patients.

CONCLUSIONS

Our results show that high plasma OPN levels are associated with distant metastases and poor survival in RCC patients. The use of OPN as potential marker to monitor new treatment strategies in patients with advanced RCC should be evaluated in prospective studies.

Renal cell carcinoma: Current status and emerging therapies

Renal cell carcinoma (RCC) accounts for about 3% of all adult malignancies and its incidence is increasing. Smoking, obesity, and end-stage renal disease are important risk factors. Localized RCC may be cured with surgical excision. However, over one-third of patients eventually develop metastatic disease. While chemotherapy and radiation therapy are relatively ineffective for RCC, immunotherapy modestly extends survival and may lead to tumor regression and long-term survival in a small minority of patients. Recently, research into the pathology of genetic syndromes associated with RCC has led to remarkable advances in our understanding of the pathogenesis of sporadic RCC. Rational therapeutic agents developed from this understanding have established new treatment paradigms for this disease.

Perspectives of proteomics in acute myeloid leukemia

Acute myeloid leukemia (AML) is a frequent hematological malignancy. Despite enormous therapeutic efforts that range from various cytotoxic agents to allogeneic stem cell transplantation, overall survival of patients with AML remains unsatisfying. The poor survival rates are mainly due to therapy-related mortality, failure of induction chemotherapy and early relapses. Therefore, novel therapeutic agents that are more efficient and better tolerated are eagerly sought after. For existing therapeutic strategies, there is a lack of markers that are capable of reliably predicting prognosis or the therapeutic response prior to treatment. There is hope that elucidation of the AML-specific proteome will prompt the discovery of novel therapeutic targets and biomarkers in AML. Modern mass-spectrometry instrumentation has achieved excellent performance in terms of sensitivity, resolution and mass accuracy; however, so far, the contribution of proteomics to the care of patients with AML is virtually zero. This might be partly because mass spectrometry instrumentation and protein fractionation still lack true high-throughput capabilities with highest levels of reproducibility, thus hampering large-scale translational studies with clinical samples. Since mass-spectrometry instruments are very intricate devices, their successful operation will hinge on the willingness and ability of mass-spectrometry experts and clinical researchers to adopt new views, learn from each other and cooperate in order to ultimately benefit the patient suffering from AML. This review highlights some clinical problems circumventing the treatment of patients with AML. Furthermore, it provides a brief overview of the technical background of standard proteomics approaches and describes opportunities, challenges and pitfalls of proteomic studies with regards to AML.