Tissue biomarkers in renal cell carcinoma: issues and solutions

DNA Methylation as Drug Sensitivity Marker in RCC: A Systematic Review

Patient response after treatment of renal cell cancer (RCC) with systemic agents, which include various drug categories, is generally poor and unpredictable. In this context, the ideal drug administration includes tools to predict the sensitivity of the disease to therapy. The aim of this study was to systematically summarize the reports on the predictive value of the methylation status in the systemic therapy of RCC. Only original articles reporting on the association of promoter methylation with the response of patients or cell lines to systemic agents were included in this review. We applied PRISMA recommendations to the structure and methodology of this systematic review. Our literature search concluded with 31 articles conducted on RCC cell lines and patient tissues. The majority of the studies demonstrated a methylation-dependent response to systemic agents. This correlation suggests that the methylation pattern can be used as a predictive tool in the management of RCC with various classes of systemic agents. However, although methylation biomarkers show promise for predicting response, the evidence of such correlation is still weak. More studies on the gene methylation pattern in patients under systemic therapy and its correlation with different degrees of response are needed.

Dynamic changes of SCGN expression imply different phases of clear cell renal cell carcinoma progression

The secretagogin (SCGN) was originally identified as a secreted calcium-binding protein present in the cytoplasm. Recent studies have found that SCGN has a close relationship with cancer. However, its role in the occurrence, progression, and prognosis of clear cell renal cell carcinoma (ccRCC) remains unclear. In this study, we utilized a mutual authentication method based on public databases and clinical samples to determine the role of SCGN in the progression and prognosis of ccRCC. Firstly, we comprehensively analyzed the expression characteristics of SCGN in ccRCC in several public databases. Subsequently, we systematically evaluated SCGN expression on 252 microarrays of ccRCC tissues from different grades. It was found that SCGN was absent in all the normal kidney tissues and significantly overexpressed in ccRCC tumor tissues. In addition, the expression level of SCGN gradually decreased with an increase in tumor grade, and the percentage of SCGN staining positivity over 50% was 86.7% (13/15) and 73.4% (58/79) in Grade1 and Grade2, respectively, while it was only 8.3% (12/144) in Grade3, and the expression of SCGN was completely absent in Grade4 (0/14) and distant metastasis group (0/4). Additionally, the expression of SCGN was strongly correlated with the patient's prognosis, with the higher the expression levels of SCGN being associated with longer overall survival and disease-free survival of patients. In conclusion, our results suggest that reduced expression of SCGN in cancer cells is correlated with the progression and prognosis of ccRCC.

Translational proteomics and phosphoproteomics: Tissue to extracellular vesicles

We are currently experiencing a rapidly developing era in terms of translational and clinical medical sciences. The relatively mature state of nucleic acid examination has significantly improved our understanding of disease mechanism and therapeutic potential of personalized treatment, but misses a large portion of phenotypic disease information. Proteins, in particular phosphorylation events that regulates many cellular functions, could provide real-time information for disease onset, progression and treatment efficacy. The technical advances in liquid chromatography and mass spectrometry have realized large-scale and unbiased proteome and phosphoproteome analyses with disease relevant samples such as tissues. However, tissue biopsy still has multiple shortcomings, such as invasiveness of sample collection, potential health risk for patients, difficulty in protein preservation and extreme heterogeneity. Recently, extracellular vesicles (EVs) have offered a great promise as a unique source of protein biomarkers for non-invasive liquid biopsy. Membranous EVs provide stable preservation of internal proteins and especially labile phosphoproteins, which is essential for effective routine biomarker detection. To aid efficient EV proteomic and phosphoproteomic analyses, recent developments showcase clinically-friendly EV techniques, facilitating diagnostic and therapeutic applications. Ultimately, we envision that with streamlined sample preparation from tissues and EVs proteomics and phosphoproteomics analysis will become routine in clinical settings.

Biomarkers for Renal Cell Carcinoma Recurrence: State of the Art

PURPOSE OF REVIEW

We aim to summarize the current state of art about the possible use of biomarkers for predicting renal cell carcinoma (RCC) recurrence after curative treatment. In addition, we aim to provide a snapshot about the clinical implication of biomarkers use for follow-up planification.

RECENT FINDINGS

A wide variety of biomarkers have been proposed. RCC biomarkers have been individuated in tumoral tissue, blood, and urine. A variety of molecules, including proteins, DNA, and RNA, warrant a good accuracy for RCC recurrence and progression prediction. Their use in prediction models might warrant a better patients' risk stratification. Future prognostic models will probably include a combination of classical features (tumor grade, stage, etc.) and novel biomarkers. Such models might allow a more accurate treatment and follow-up planification.

Metabolomic Analysis to Elucidate Mechanisms of Sunitinib Resistance in Renal Cell Carcinoma

Metabolomics analysis possibly identifies new therapeutic targets in treatment resistance by measuring changes in metabolites accompanying cancer progression. We previously conducted a global metabolomics (G-Met) study of renal cell carcinoma (RCC) and identified metabolites that may be involved in sunitinib resistance in RCC. Here, we aimed to elucidate possible mechanisms of sunitinib resistance in RCC through intracellular metabolites. We established sunitinib-resistant and control RCC cell lines from tumor tissues of RCC cell (786-O)-injected mice. We also quantified characteristic metabolites identified in our G-Met study to compare intracellular metabolism between the two cell lines using liquid chromatography-mass spectrometry. The established sunitinib-resistant RCC cell line demonstrated significantly desuppressed protein kinase B (Akt) and mesenchymal-to-epithelial transition (MET) phosphorylation compared with the control RCC cell line under sunitinib exposure. Among identified metabolites, glutamine, glutamic acid, and α-KG (involved in glutamine uptake into the tricarboxylic acid (TCA) cycle for energy metabolism); fructose 6-phosphate, D-sedoheptulose 7-phosphate, and glucose 1-phosphate (involved in increased glycolysis and its intermediate metabolites); and glutathione and myoinositol (antioxidant effects) were significantly increased in the sunitinib-resistant RCC cell line. Particularly, glutamine transporter (SLC1A5) expression was significantly increased in sunitinib-resistant RCC cells compared with control cells. In this study, we demonstrated energy metabolism with glutamine uptake and glycolysis upregulation, as well as antioxidant activity, was also associated with sunitinib resistance in RCC cells.

Correlative serum biomarker analyses in the phase 2 trial of lenvatinib-plus-everolimus in patients with metastatic renal cell carcinoma

Background

No biomarkers have been established to predict treatment efficacy in renal cell carcinoma (RCC). In an exploratory retrospective analysis of a Phase 2 study, we constructed composite biomarker scores (CBSs) to predict progression-free survival (PFS) and overall survival (OS) in patients with metastatic RCC randomised to receive lenvatinib-plus-everolimus.

Methods

Of 40 biomarkers tested, the 5 most strongly associated with PFS (HGF, MIG, IL-18BP, IL-18, ANG-2) or OS (TIMP-1, M-CSF, IL-18BP, ANG-2, VEGF) were used to make a 5-factor PFS-CBS or OS-CBS, respectively. A 2-factor CBS was generated with biomarkers common to PFS-CBS and OS-CBS. Patients were divided into groups accordingly (5-factor-CBS high: 3−5, CBS-low: 0–2; 2-factor-CBS high: 1–2, CBS-low: 0).

Results

PFS/OS with lenvatinib-plus-everolimus were significantly longer in the 5-factor CBS-high group versus the CBS-low group (P = 0.0022/P < 0.0001, respectively). In the CBS-high group, PFS/OS were significantly longer with lenvatinib-plus-everolimus versus everolimus (P < 0.001/P = 0.0079, respectively); PFS was also significantly longer with lenvatinib-plus-everolimus versus lenvatinib (P = 0.0046). The 5-factor-CBS had a predictive role in PFS and OS after multivariate analysis. Similar trends were observed with the 2-factor-CBS for PFS (i.e., lenvatinib-plus-everolimus versus everolimus).

Conclusions

The 5-factor CBS may identify patients with metastatic RCC who would benefit from lenvatinib-plus-everolimus versus everolimus; additional validation is required.

Clinical trial registration

The clinical trial registration number is NCT01136733.

PD-L1 Expression and Clinical Outcomes to Cabozantinib, Everolimus, and Sunitinib in Patients with Metastatic Renal Cell Carcinoma: Analysis of the Randomized Clinical Trials METEOR and CABOSUN

PURPOSE

Programmed death-ligand 1 (PD-L1) status by IHC is prognostic in metastatic renal cell carcinoma (mRCC), and its role as a potential predictive biomarker is under investigation. Using tumor tissue from the METEOR (NCT01865747) and CABOSUN (NCT01835158) clinical trials, we explored whether PD-L1 expression and the extent of the immune cell infiltrate can serve as prognostic and/or predictive biomarkers for cabozantinib and other targeted agents.

EXPERIMENTAL DESIGN

IHC double staining for PD-L1 and CD45/CD163 (immune cell markers) was performed on tumor tissue from METEOR (n = 306) and CABOSUN (n = 110) clinical trials. Immune cell density and MET expression levels were also analyzed. Our primary aim was to correlate progression-free survival (PFS) by independent central review with PD-L1 status in patients treated with cabozantinib, everolimus (METEOR), or sunitinib (CABOSUN). Overall survival (OS) was also interrogated.

RESULTS

Tumor cell (TC) PD-L1 expression (≥1% cutoff) was detected in 29% and 23% of tumors from patients in the METEOR and CABOSUN trials, respectively. On univariate analysis, patients with PD-L1-positive TC had poorer PFS and OS than patients with PD-L1-negative TC on both trials, independent of therapy. On multivariable analysis and when combining the two trials, the association between TC PD-L1 expression and OS was statistically significant for all patients (P = 0.034) and for patients treated with cabozantinib only (P = 0.038). Cabozantinib was associated with improved PFS (HR < 0.70) and OS (HR < 0.85) compared with everolimus and sunitinib irrespective of PD-L1 expression.

CONCLUSIONS

Higher PD-L1 expression results in worse clinical outcomes in mRCC treated with targeted therapy. Furthermore, PD-L1 expression is not predictive of response to cabozantinib therapy.

Therapeutic Sequencing in Metastatic Renal Cell Carcinoma

The influx of multiple novel therapeutic options in the mRCC field has brought a challenge for treatment sequencing in this disease. In the past few years, cabozantinib, nivolumab and the combination of lenvatinib and everolimus have been approved in the second-line setting. As there is no direct comparison between these agents and the studies have failed to show improved benefit among a biomarker-selected patient population, appropriate patient selection based on clinical factors for individualized therapy is critical. Herein we provide a comprehensive overview of current data from each agent through the discussion of disease biology, clinical trials, potential biomarkers and distilling future perspectives in the field.

Management of poor-risk metastatic renal cell carcinoma: current approaches, the role of temsirolimus and future directions

Targeted therapies have substantially improved outcomes in metastatic renal cell carcinoma (mRCC). As expected, poor-risk patients have the worst outcomes. Temsirolimus is currently the only agent licensed for treatment of poor-risk mRCC patients. It is associated with meaningful improvements in survival and quality of life, highlighting the importance of correctly stratifying risk in mRCC patients so they receive optimal treatment. Currently, data for other targeted therapies in poor-risk patients are relatively sparse. Optimizing outcomes in these patients is the subject of ongoing research, including studies of biomarkers and studies to elucidate the role of nephrectomy and neoadjuvant targeted therapy in poor-risk mRCC patients. The impacts of novel combinations including temsirolimus have also been explored to further improve outcomes.

NMR metabolomics of renal cancer: an overview

This paper reviews the use of NMR metabolomics for the metabolic characterization of renal cancer. The existing challenges in the clinical management of this disease are first presented, followed by a brief introduction to the metabolomics approach, in the context of cancer research. A subsequent review of the literature on NMR metabolic studies of renal cancer reveals that the subject has been clearly underdeveloped, compared with other types of cancer, particularly regarding cultured cells and tissue analysis. NMR analysis of biofluids has focused on blood (plasma or serum) metabolomics, comprising no account of studies on human urine, in spite of its noninvasiveness and physiological proximity to the affected organs. Finally, some areas of potential future development are identified.

Harnessing the PD-1 pathway in renal cell carcinoma: current evidence and future directions

Programmed cell death-1 (PD-1) is a recognized immune checkpoint. It is frequently upregulated on the T cells that infiltrate tumors, providing an inhibitory signal, which may facilitate immune escape. Blocking antibodies have been developed to interrupt the interaction of PD-1 with its ligands PD-L1/PD-L2, with the goal of increasing the host antitumor immune response. Initial results have been encouraging, with durable responses in both treatment-naive and pretreated patients, along with an acceptable toxicity profile. This tolerability makes PD-1 blockade an excellent potential partner for combination strategies with the approved targeted agents, such as tyrosine kinase inhibitors (TKIs) and anti-vascular endothelial growth factor (anti-VEGF) antibodies, as well as other investigational immune checkpoint inhibitors or agonist antibodies that may costimulate an immune response. PD-L1 expression on tumor cells and tumor-infiltrating immune cells is also being evaluated as a predictive biomarker of response to treatment. This review summarizes the biological basis, preclinical studies, ongoing trials, and future challenges associated with targeting the PD-1 pathway in renal cell carcinoma.

Subverting the B7-H1/PD-1 pathway in advanced melanoma and kidney cancer

Ligands for inhibitory immune receptors on T cells may be constitutively expressed on tumor cells or host cells in tumor microenvironment as a consequence of adaptive immunity. Programmed death 1 (PD-1) is 1 such receptor on T cells, which functions as a negative regulator of T cell activity. Tumors that up-regulate programmed death ligand 1 (PD-L1) (B7-H1) may abrogate the host's effector T cell antitumor response. Higher tumoral PD-L1 expression has been linked with inferior clinical outcomes. Multiple cancers including renal cell cancers (RCCs) and melanomas have relatively high levels of PD-L1 on the cell surface. Early evaluations of antibodies that block the interaction of PD-1 and PD-L1 have shown efficacy and a favorable tolerability profile with notable inflammatory toxicities that are generally manageable. Upward of 30% of RCC patients and 50% of melanoma patients achieve objective responses. Durable responses can occur, even in some patients who have discontinued treatment. The developing investigation of PD-1/PD-L1 pathway-blocking agents in RCC and melanoma will likely alter our approaches to the treatment of these 2 deadly diseases.

Relative mRNA expression of prostate-derived E-twenty-six factor and E-twenty-six variant 4 transcription factors, and of uridine phosphorylase-1 and thymidine phosphorylase enzymes, in benign and malignant prostatic tissue

Prostate cancer is the most frequent urological tumor, and the second most common cancer diagnosed in men. Incidence and mortality are variable and appear to depend on behavioral factors and genetic predisposition. The prostate-derived E-twenty-six factor (PDEF) and E-twenty-six variant 4 (ETV4) transcription factors, and the thymidine phosphorylase (TP) and uridine phosphorylase-1 (UP-1) enzymes, are reported to be components of the pathways leading to tumorigenesis and/or metastasis in a number of tumors. The present study aimed to analyze the mRNA expression levels of these proteins in prostatic cancerous and benign tissue, and their association with clinical and pathological variables. Using quantitative reverse transcription polymerase chain reaction, the mRNA expression levels of PDEF, ETV4, TP and UP-1 were studied in 52 tissue samples (31 of benign prostatic hyperplasia and 21 of prostate adenocarcinomas) obtained from patients treated by transurethral resection of the prostate or by radical prostatectomy. Relative expression was assessed using the ∆-CT method. Data was analyzed using Spearman's tests for correlation. P<0.05 was considered to indicate a statistically significant difference. The results revealed that PDEF, ETV4, UP-1 and TP were expressed in 85.7, 90.5, 95.2 and 100% of the prostate cancer samples, and in 90.3, 96.8, 90.3 and 96.8% of the benign samples, respectively. PDEF and ETV4 exhibited a significantly higher relative expression level in the tumor samples compared with their benign counterparts. The relative expression of TP and UP-1 did not differ significantly between benign and cancerous prostate tissues. The relative expression of TP was moderately and significantly correlated with the expression of ETV4 in the benign tissues. The relative expression of UP-1 was significantly lower in T3 compared with T1 and T2 cancers. These findings indicate that PDEF, ETV4, TP and UP-1 are typically expressed in benign and malignant prostatic tissues. Further studies are necessary to define the role of these proteins as therapeutic targets in prostate cancer.

PD-1 blockade in renal cell carcinoma: to equilibrium and beyond

The past several years have witnessed a resurgence of interest in cancer immunotherapy. The development of blocking antibodies against the inhibitory programmed death-1 (PD-1) pathway represents a clinical breakthrough in the treatment of solid tumors such as melanoma, and these agents show great promise in renal cell carcinoma (RCC). The early data have been surprising in that they demonstrate that blockade of a single immune checkpoint can elicit objective responses in patients with RCC, despite the recognized complexity of the immunosuppressive tumor microenvironment. Reinvigorating the patient's own immune cells to reactivate and to target the tumor has the potential advantages of more selective killing and thus decreased toxicity. In addition, checkpoint blockade immunotherapy has the advantage of inducing a memory response that is unattainable with our current cytotoxic and targeted therapies. This Crossroads overview will highlight the emerging investigation of PD-1 blockade in RCC and how this T cell-targeted strategy may thwart the tumor's escape mechanisms and shift the immune system/tumor balance back to a state of equilibrium and even to tumor elimination.

Prognostic value of carbonic anhydrase IX immunohistochemical expression in renal cell carcinoma: a meta-analysis of the literature

Background

Carbonic anhydrase IX (CAIX) protein has been correlated with progression and survival in patients with renal cell carcinoma (RCC). The prognostic value of CAIX in RCC however, remains inconclusive according to published works. This study aimed to analyze CAIX as a biological marker to predict RCC patient prognosis.

Methods

A literature search of the PubMed and Web of Knowledge databases was performed to retrieve original studies from their inception to December of 2013. Fifteen studies, collectively including a total of 2611 patients with renal cell carcinoma, were carefully reviewed. Standard meta-analysis methods were applied to evaluate the prognostic impact of CAIX expression on patient prognosis. The hazard ratio (HR) and its 95% confidence interval (CI) were recorded for the relationship between CAIX expression and survival, and the data were analyzed using Review Manager 5.2 software and Stata software 11.0.

Results

In patients with RCC, low CAIX expression was associated with poor disease-specific survival (HR = 1.89, 95% CI: 1.20–2.98, P = 0.006), unfavorable progression-free survival (HR = 2.62, 95% CI: 1.14–6.05, P = 0.02) and worse overall survival (HR = 2.03, 95% CI: 1.28–3.21, P = 0.002). Furthermore, low CAIX expression was significantly associated with the presence of lymph node metastases (odds ratio (OR) = 0.31, 95% CI = 0.15–0.62, P = 0.0009) and distant metastases (OR = 0.66, 95% CI = 0.46–0.96, P = 0.03) and predicted a higher tumor grade (OR = 0.41, 95% CI = 0.31–0.54, P<0.00001).

Conclusions

Low CAIX expression most likely indicates poor prognosis in RCC patients. Moreover, low CAIX expression was significantly associated with unfavorable clinicopathological factors. To strengthen our findings, further well-designed prospective studies should be conducted to investigate the role of CAIX expression in RCC.

Analysis and validation of tissue biomarkers for renal cell carcinoma using automated high-throughput evaluation of protein expression

The objective of this study was to compare the predictive ability of potential tissue biomarkers to known prognostic factors that predict renal cell carcinoma (RCC) recurrence using an automated system of immunohistochemical analysis. After institutional review board approval, a tissue microarray was constructed using tissue from patients who had partial or radical nephrectomy for RCC. Patients with metastatic disease were excluded. Immunohistochemical staining of the tissue microarray for Ki-67, C-reactive protein, carbonic anhydrase 9, and hypoxia-inducible factors 1α and 2α was analyzed using automated image analysis. Univariable and multivariable analyses were performed to evaluate the association of putative biomarkers and known prognostic factors. Of 216 patients who met the entrance criteria, 34 (16%) patients developed metastatic recurrence within a median follow-up interval of 60.9 (interquartile range, 13.9-87.1) months. RCC morphotypes analyzed in this study include clear cell (n = 156), papillary (n = 38), chromophobe (n = 16), and collecting duct/unclassified (n = 6). Univariate analysis identified that only increased Ki-67 was predictive of RCC recurrence among the proteins evaluated, in addition to other known clinicopathological prognostic factors. After multivariate analysis, Ki-67 was identified as an independently predictive risk factor for RCC recurrence (hazard ratio [HR], 3.73 [confidence interval {CI}, 1.60-8.68]). Other independent predictors of RCC recurrence included tumor diameter (HR, 1.20 [CI, 1.02-1.41]) and perinephric fat invasion (HR, 4.49 [CI, 1.11-18.20]). We conclude that Ki-67 positivity is independently predictive of RCC recurrence after surgery in nonmetastatic patients. Automated analysis of tissue protein expression can facilitate a more objective and expedient investigation of tissue biomarkers for RCC.

Renal tumors: diagnostic and prognostic biomarkers

The International Society of Urological Pathology convened a consensus conference on renal cancer, preceded by an online survey, to address issues relating to the diagnosis and reporting of renal neoplasia. In this report, the role of biomarkers in the diagnosis and assessment of prognosis of renal tumors is addressed. In particular we focused upon the use of immunohistochemical markers and the approach to specific differential diagnostic scenarios. We enquired whether cytogenetic and molecular tools were applied in practice and asked for views on the perceived prognostic role of biomarkers. Both the survey and conference voting results demonstrated a high degree of consensus in participants' responses regarding prognostic/predictive markers and molecular techniques, whereas it was apparent that biomarkers for these purposes remained outside the diagnostic realm pending clinical validation. Although no individual antibody or panel of antibodies reached consensus for classifying renal tumors, or for confirming renal metastatic disease, it was noted from the online survey that 87% of respondents used immunohistochemistry to subtype renal tumors sometimes or occasionally, and a majority (87%) used immunohistochemical markers (Pax 2 or Pax 8, renal cell carcinoma [RCC] marker, panel of pan-CK, CK7, vimentin, and CD10) in confirming the diagnosis of metastatic RCC. There was consensus that immunohistochemistry should be used for histologic subtyping and applied before reaching a diagnosis of unclassified RCC. At the conference, there was consensus that TFE3 and TFEB analysis ought to be requested when RCC was diagnosed in a young patient or when histologic appearances were suggestive of the translocation subtype; whereas Pax 2 and/or Pax 8 were considered to be the most useful markers in the diagnosis of a renal primary.

The role of aberrant VHL/HIF pathway elements in predicting clinical outcome to pazopanib therapy in patients with metastatic clear-cell renal cell carcinoma

PURPOSE

Inactivation of von Hippel-Lindau (VHL) gene in clear-cell renal cell carcinoma (RCC) leads to increased levels of hypoxia-inducible factors (HIF) and overexpression of HIF target genes, such as VEGF and others. VEGF-targeted agents are standard in advanced clear-cell RCC but biomarkers of activity are lacking.

EXPERIMENTAL DESIGN

We analyzed tumor tissue samples from metastatic clear-cell RCC patients who received pazopanib as part of clinical trial VEG102616. We evaluated several components of the VHL/HIF pathway: VHL gene inactivation (mutation and/or methylation), HIF-1α and HIF-2α immunohistochemistry staining, and HIF-1α transcriptional signature. We evaluated the association of these biomarkers with best overall response rate (ORR) and progression-free survival (PFS) to pazopanib, a standard first-line VEGF-targeted agent.

RESULTS

The VEG102616 trial enrolled 225 patients, from whom 78 samples were available for tumor DNA extraction. Of these, 70 patients had VHL mutation or methylation. VHL gene status did not correlate with ORR or PFS. Similarly, HIF-1α (65 samples) and HIF-2α (66 samples) protein levels (high vs. low) did not correlate with ORR or PFS to pazopanib. The HIF-1α transcriptional signature (46 samples) was enriched in tumors expressing high HIF-1α levels. However, the HIF-1α gene expression signature was not associated with clinical outcome to pazopanib.

CONCLUSIONS

In patients with advanced clear-cell RCC, several potential biomarkers along the VHL/HIF-1α/HIF-2α axis were not found to be predictive for pazopanib activity. Additional efforts must continue to identify biomarkers associated with clinical outcome to VEGF-targeted agents in metastatic RCC.

Novel immunotherapeutic strategies in development for renal cell carcinoma

CONTEXT

The purpose of this report is to review immunotherapies under investigation for patients with renal cell carcinoma (RCC), the most common form of kidney cancer, for which the incidence and mortality rate continue to increase.

OBJECTIVE

To summarize and evaluate current data on immunotherapies for RCC and discuss issues to be resolved before integration into the RCC treatment paradigm.

EVIDENCE ACQUISITION

A search of Medline, clinicaltrials.gov, and congress abstracts/treatment guidelines was performed in May 2012 using the following terms (and variations): metastatic renal cell carcinoma, practice guidelines, response/resistance to current treatments, immunotherapy, novel immunotherapeutic strategies, T-cell modulation, immune priming, innate immunity, and combination therapy.

EVIDENCE SYNTHESIS

Prior to the advent of novel agents targeting the vascular endothelial growth factor and mechanistic target of rapamycin pathways, interleukin-2 (IL-2) and interferon-α were the mainstays of RCC treatment. IL-2 remains one of the only treatments capable of curing advanced RCC, albeit in few patients. Despite recent advances, unmet need still exists for patients in the adjuvant setting, those with poor prognostic factors, and those who have progressed on prior targeted therapies. Improved understanding of host-tumor immune interactions has led to development of novel immunotherapeutic agents, including antibodies against immune checkpoint proteins (eg, programmed death-1 and cytotoxic T-lymphocyte antigen-4), and various vaccines. Because many of these compounds are in development, clinical experience with them is limited, although some have demonstrated activity in preliminary studies.

CONCLUSIONS

It is not yet clear where these new immunotherapies will fit into RCC treatment paradigms, but they may provide new options for patients whose current choices are limited. Furthermore, predictive biomarkers are needed to identify patients who will derive the greatest benefit from immunotherapy.

Biomarkers: the next therapeutic hurdle in metastatic renal cell carcinoma

Despite recent advances, metastatic renal cell carcinoma remains largely an incurable disease. Vascular endothelial growth factor and mammalian target of rapamycin inhibitors have provided improvements in clinical outcomes. High-dose interleukin 2 remains an option for highly selected patients and is associated with durable remissions in a small minority of patients. The toxicity profiles of specific agents and patient characteristics and comorbidities and costs have an important role in the current choice of therapy. Major challenges encountered in developing molecular biomarkers to guide therapy are tumour heterogeneity and standardisation of tissue collection and analysis. Although biomarkers are in their infancy of development, they should be a priority in early preclinical and clinical development in order to guide rational tailored development of emerging agents.

Down-regulation of PKCζ in renal cell carcinoma and its clinicopathological implications

Background

Metastatic renal cell carcinoma (RCC) is highly resistant to systemic chemotherapy. Unfortunately, nearly all patients die of the metastatic and chemoresistant RCC. Recent studies have shown the atypical PKCζ is an important regulator of tumorigenesis. However, the correlation between PKCζ expression and the clinical outcome in RCC patients is unclear. We examined the level of PKCζ expression in human RCC.

Methods

PKCζ mRNA and protein expressions were examined by real-time polymerase chain reaction (PCR) and immunohistochemistry (IHC) respectively in RCC tissues of 144 patients. Cellular cytotoxicity and proliferation were assessed by MTT.

Results

PKCζ expression was significantly higher in normal than in cancerous tissues (P < 0.0001) by real-time PCR and IHC. Similarly, PKCζ expression was down-regulated in four renal cancer cell lines compared to immortalized benign renal tubular cells. Interestingly, an increase of PKCζ expression was associated with the elevated tumor grade (P = 0.04), but no such association was found in TNM stage (P = 0.13). Tumors with higher PKCζ expression were associated with tumor size (P = 0.048). Expression of higher PKCζ found a poor survival in patients with high tumor grade. Down-regulation of PKCζ showed the significant chemoresistance in RCC cell lines. Inactivation of PKCζ expression enhanced cellular resistance to cisplatin and paclitaxel, and proliferation in HK-2 cells by specific PKCζ siRNA and inhibitor.

Conclusions

PKCζ expression was associated with tumorigenesis and chemoresistance in RCC.

Prognostic factors in renal cell carcinoma

PURPOSE

Renal cell carcinoma (RCC) is a very heterogeneous disease with widely varying prognosis. An accurate knowledge of the individual risk of disease progression and mortality after treatment is essential to counsel patients, plan individualized surveillance protocols and select patients for adapted treatment schedules and new clinical trials.

METHODS

A systematic review of the literature on prognostic factors of localized and metastatic RCC was performed.

RESULTS

Prognostic factors in RCC include anatomical (TNM classification, tumor size), histological (Fuhrman grade, histologic subtype), clinical (symptoms and performance status), and molecular features. All these features are not perfectly accurate when used alone. Therefore an increasing number of prognostic models or nomograms that include several combined prognostic features have been designed in order to improve predictive accuracy. UCLA Integrated Staging System (UISS) and the Mayo Clinic's SSIGN score are the two most used prognostic models for localized RCC. In the setting of metastatic RCC the classical anatomical and histological tumor features have little predictive value. However, accurate prognostic models have been designed to predict response to therapy, and progression-free and overall survival. The two most used tools to predict response to immunotherapy are the model designed by the French Group of Immunotherapy and the Motzer's model. The advent of tyrosine kinase inhibitors and antiangiogenic drugs have deeply changed the treatment of metastatic RCC. Predictive tools that are adapted to the modern targeted therapies are now needed.

CONCLUSION

There is increasing knowledge on prognostic factors of localized and metastatic RCC. Several predictive models have been developed by combining different prognostic features and are valuable tools for patient counseling, treatment decision-making and trial design. Further research is needed to assess whether the combination of classical prognostic factors with molecular features and information from gene and protein expression profiling can increase the predictive accuracy of the current prognostic models.

Dysregulation of kallikrein-related peptidases in renal cell carcinoma: potential targets of miRNAs

Renal cell carcinoma (RCC) accounts for 3% of all adult malignancies and currently no diagnostic marker exists. Kallikrein-related peptidases (KLKs) have been implicated in numerous cancers including ovarian, prostate, and breast carcinoma. KLKs 5, 6, 10, and 11 have decreased expression in RCC when compared to normal kidney tissue. Our bioinformatic analysis indicated that theKLK 1,6, and7genes have decreased expression in RCC. We experimentally verified these results and found that decreased expression ofKLKs 1and3were significantly associated with the clear cell RCC subtype (p<0.001). An analysis of miRNAs differentially expressed in RCC showed that 61 of the 117 miRNAs that were reported to be dysregulated in RCC were predicted to target KLKs. We experimentally validated two targets using two independent approaches. Transfection of miR-224 into HEK-293 cells resulted in decreased KLK1 protein levels. A luciferase assay demonstrated that hsa-let-7f can target KLK10 in the RCC cell line ACHN. Our results, showing differential expression of KLKs in RCC, suggest that KLKs could be novel diagnostic markers for RCC and that their dysregulation could be under miRNA control. The observation that KLKs could represent targets for miRNAs suggests a post-transcriptional regulatory mechanism with possible future therapeutic applications.