Identification of the genes for kidney cancer: opportunity for disease-specific targeted therapeutics

Rationale for immune checkpoint inhibitors plus targeted therapy for advanced renal cell carcinoma

Renal cell carcinoma (RCC) is a frequent urological malignancy characterized by a high rate of metastasis and lethality. The treatment strategy for advanced RCC has moved through multiple iterations over the past three decades. Initially, cytokine treatment was the only systemic treatment option for patients with RCC. With the development of medicine, antiangiogenic agents targeting vascular endothelial growth factor and mammalian target of rapamycin and immunotherapy, immune checkpoint inhibitors (ICIs) have emerged and received several achievements in the therapeutics of advanced RCC. However, ICIs have still not brought completely satisfactory results due to drug resistance and undesirable side effects. For the past years, the interests form researchers have been attracted by the combination of ICIs and targeted therapy for advanced RCC and the angiogenesis and immunogenic tumor microenvironmental variations in RCC. Therefore, we emphasize the potential principle and the clinical progress of ICIs combined with targeted treatment of advanced RCC, and summarize the future direction.

The Non-Interventional PAZOREAL Study to Assess the Effectiveness and Safety of Pazopanib in a Real-Life Setting: Reflecting a Changing mRCC Treatment Landscape

The approval of tyrosine kinase inhibitors and checkpoint inhibitors represented a remarkable progression in the therapeutic landscape for the treatment of metastatic renal cell carcinoma (mRCC). Yet, in the ever-evolving landscape of mRCC treatment, real-world data on these agents, including pazopanib, are scarce. The non-interventional PAZOREAL study investigated the effectiveness and safety of pazopanib (first-line), nivolumab (second-line), and everolimus (second- and third-line) in a real-life setting. The multicentric study included 376 mRCC patients who received first-line treatment with pazopanib and assessed time on the drug (primary endpoint), overall survival, best responses, disease control rates, as well as safety signals and health-related quality of life. The median overall time on the drug was 10.0 months, with first-line pazopanib having a median time on drug of 6.3 months. The median overall survival was 35.9 months. The disease control rate for first-line pazopanib was 56.9%. No new safety signals were detected. PAZOREAL provides valuable real-world data for first-line treatment with pazopanib.

Case report: Going through pregnancy safely after twice partial nephrectomy for bilateral kidneys with HLRCC-associated RCC

Background

HLRCC-associated RCC (hereditary leiomyomatosis and renal cell cancer-associated renal cell carcinoma) caused by germline mutations of the fumarate hydratase (FH) gene is a rare autosomal dominant genetic renal cancer. At present, there are no reports of bilateral kidneys with HLRCC-associated RCC, let alone safe pregnancy after twice partial nephrectomy for bilateral kidney HLRCC-associated RCC.

Case presentation

We report a 25-year-old woman with bilateral renal tumors detected by ultrasound screening during a routine checkup. CT revealed a soft tissue mass in the parenchyma of the left kidney and a nodular soft tissue mass in the lower pole of the right kidney. She underwent robot-assisted laparoscopic left partial nephrectomy and underwent laparoscopic right partial nephrectomy 3 months after the first surgery. Heterozygous mutation in the FH gene on the patient’s tumor tissue was detected by genetic testing. Combined with the patient’s medical history, microstructure and immunohistochemical staining of tumor tissue, and genetic test results, the pathological reports after two operations concluded HLRCC-associated RCC. Then, she was injected with interferon and nivolumab as a preventative treatment against tumor recurrence. Up to 38 months after surgery, having given birth to a baby, till now there was no tumor progression.

Conclusions

This is a clinically significant case, as it provides a reference for pregnancy in patients undergoing partial nephrectomy for bilateral kidneys with HLRCC-associated RCC and may indicate an effective approach to preventing tumor recurrence by nivolumab in patients with HLRCC-associated RCC.

[Biomarkers for renal cell tumours]

During the last three decades, renal tumours have become increasingly well differentiated on the basis of their histopathological and molecular features. This subtyping has increasingly impacted clinical practice because more therapeutic options are available in organ-confined and metastatic renal cell tumours. The knowledge of the underlying molecular alterations is essential to develop molecular targeted therapies and to select the most effective systemic therapy for each patient. This manuscript gives an overview of the molecular differentiation on the one hand, and on diagnostic, prognostic and predictive biomarkers on the other hand.

Standardized Incidence Rate, Risk and Survival Outcomes of Second Primary Malignancy Among Renal Cell Carcinoma Survivors: A Nested Case-Control Study

Purpose

Second primary malignancy (SPM) is challenging for treatment and long-term survival. We sought to investigate the standardized incidence rate (SIR), risk factors, and survival outcomes for SPM after renal cell carcinoma (RCC) treatment.

Method

A nested case-control study was designed, we identified all T1-4N0-1M0 RCC patients diagnosed between 2004 and 2015 in the Surveillance, Epidemiology, and End Results database and followed them for SPM diagnosis for up to 13 years. Patients with SPM diagnosis ≥6 months after treatment of primary T1-4N0-1M0 RCC were identified as the case cohort and SPM-free patients were the control cohort. SIRs and the excess risk were calculated. A competing risks and Cox model were used to evaluate the risk factors of SPM and overall survival (OS).

Results

A cohort of 6,204 RCC patients with SPM were matched with a control group of 31,020 RCC patients without SPM. The median time-to-SPM interval was 54.5 months in RCC patients with SPM diagnosis. Besides, an SPM of T3/4 or/and M1 stage diagnosis was positively associated with a longer time-to-SPM interval. SIR of SPM increased by follow-up time and decreased with age at diagnosis (P_{for all <}0.001). SPM in the kidney had the highest SIR (54.6, P <0.001) among all SPMs. Prostate cancer (29.8%) in males and breast cancer (23.5%) in females were the most common SPM. Older age, black ethnicity, male sex, higher family income, papillary RCC, and lower TNM stage were significant risk factors for SPM diagnosis. The proportion of deaths from SPM exceeds that of deaths from RCC 3 years after the first RCC treatment. Patients with SPM and early time-to-SPM interval shortens the OS compared with SPM-free patients. The 5-year OS was 85.9% and 58.9% from the first RCC and the SPM diagnosis, respectively. Besides, patients with low-grade/early-stage SPM could benefit from aggressive surgical treatment for solid tumors.

Conclusions

Collectively, our study described the epidemiological characteristics of SPM among RCC survivors and identified the independent predictors of the SPM diagnosis and its survival outcomes. This study highlights the importance of patient education and follow-up after the surgery for RCC.

Evaluation of Multimode Color Doppler Flow Imaging in the Diagnosis of Solid Renal Tumor

Background

Renal cell carcinoma is one of the most common malignant tumors in urinary system, seriously affecting people's health and life. This study aimed to evaluate the clinical value of multi-mode color Doppler flow imaging for diagnosis of solid renal tumor.

Methods

Sixty-six renal solid tumors from 63 patients were examined by color Doppler flow imaging (CDFI), power Doppler flow imaging (PDFI), superb microvascular imaging (SMI), and contrast-enhanced ultrasound (CEUS) before surgery. The diagnostic efficacy of the four methods was compared by determining blood flow grade and ring-like blood flow with Adler's method. Chi-square test and Fisher's test were performed to compare the results of sensitivity and specificity among four methods.

Results

Statistically significant differences in blood flow grade and ring-like blood flow were observed between benign and malignant renal tumors as detected by SMI and CEUS (P < 0.05), whereas no difference was found as detected by CDFI and PDFI (P > 0.05). The results indicated that the sensitivity and specificity of SMI (82.46%, 88.89%) and CEUS (84.21%, 88.89%) were higher than those of CDFI (42.11%, 66.67%) and PDFI (47.37%, 77.78%). Compared with the abilities of CDFI and PDFI, SMI and CEUS can better display the micro-blood flow in the tumors and evaluate the blood flow grading, which indicated that SMI and CEUS may have high values in the differential diagnosis of benign and malignant solid renal tumors.

Conclusion

SMI and CEUS can improve the sensitivity and specificity of the diagnosis of benign and malignant renal tumors and have a high application value.

Anlotinib for Patients With Metastatic Renal Cell Carcinoma Previously Treated With One Vascular Endothelial Growth Factor Receptor-Tyrosine Kinase Inhibitor: A Phase 2 Trial

Introduction: Sequential therapy with vascular endothelial growth factor receptor-tyrosine kinase inhibitors (VEGFR-TKIs) is effective in some patients with metastatic renal cell carcinoma (mRCC) progressed from or were intolerant to a prior TKIs. Anlotinib is a multi-kinase inhibitor targeting VEGFR1/2/3, PDGFR and FGFR, which has demonstrated efficacy and safety in first-line treatment of mRCC. This study assessed the potential of anloitnib as second-line treatment for patients with mRCC after prior one VEGFR-TKI.

Methods: This is a single-arm, open-label, phase 2 study. Patients progressed after or were intolerant to sorafenib or sunitinib were enrolled. Anlotinib was administrated orally 12 mg once daily for 14 days every 3 weeks. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), objective response rate (ORR), safety and quality of life (QoL).

Results: Forty three patients were enrolled and 42 received anlotinib, of whom 32 progressed after and 10 were intolerant to sorafenib or sunitinib. Median PFS were 14.0 months (95% CI 8.3–20.3) and 8.5 months (95% CI 5.6–16.6) for overall population and patients progressed after a previous VEGFR-TKI, respectively. Median OS was 21.4 months (95% CI 16.0–34.5), confirmed ORR and DCR were 16.7 and 83.3% in overall population. The most common adverse events included diarrhea (47.6%), hypertension (45.2%), hand and foot syndrome (42.9%), and fatigue (40.5%). Grade 3 hematological adverse events occurred in four cases, while no grade 4 hematological adverse events was observed.

Conclusions: Anlotinib showed promising efficacy as well as favorable safety as second-line treatment for patients with mRCC.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT02072044.

Transcriptomics in RCC

Improvements in chemistry, molecular biology, genetics, and bioinformatics have allowed broad use of transcriptomic profiling. Understanding the population of ribonucleic acid (RNA) transcripts can provide important clinical information relevant to kidney cancer care. This includes a better understanding of kidney cancer subtype and distinct clusters within these categories. RNA-sequencing (RNA-seq) is typically done on a region within the tumor, which represents thousands to millions of heterogeneous cells and various components of the microenvironment. Computational tools can deconvolute these populations to provide insight into the microenvironment. Specific signatures of hypoxia, proliferation, angiogenesis and immune infiltration can predict response and survival. Prognostic signatures can risk stratify tumors to aid in identification of patients who might derive benefit from adjuvant therapy. As the cost of sequencing continues to decline and improved bioinformatic tools are developed, the barriers to clinical use of transcriptomic data continue to crumble. Here we review the current literature around the use of transcriptomics in kidney cancer diagnosis and management.

Preclinical rationale and clinical efficacy of antiangiogenic therapy and immune checkpoint blockade combination therapy in urogenital tumors

PURPOSE

In recent years, immune checkpoint blockade (ICB) therapies have shown good clinical responses in various solid cancers. However, a major challenge in the process of ICB treatment is when tumors do not have enough infiltrating T cells. Antiangiogenic drugs targeting vascular endothelial growth factor (VEGF) and its receptors have been approved for the treatment of various malignant solid tumors alone or in combination with other therapies. Our review mainly discusses the preclinical rationale and clinical efficacy of antiangiogenic and ICB combination therapy in urogenital tumors.

METHODS

We reviewed relevant literature on preclinical research and clinical trial results regarding antiangiogenic and ICB combination therapy in urogenital tumors from PubMed. In addition, we searched ongoing clinical trials on ClinicalTrials.gov to collect information related to this specific topic.

RESULTS

Antiangiogenesis therapy could enhance T cell recruitment and increase T cell infiltration into the tumor microenvironment by blocking VEGF-VEGF receptor 2 binding and downstream signaling pathways to normalize tumor blood vessels. The combination of ICB and antiangiogenesis therapy could improve antitumor activity according to subsequent preclinical experiments and several phase I/II/III clinical trials on urogenital tumors.

CONCLUSION

Combined therapy has shown some antitumor efficacy in several urogenital tumors, such as metastatic renal cell carcinoma, metastatic urothelial and genitourinary tumors, endometrial carcinoma, ovarian cancer, and fallopian tube cancer. Combination therapy is a promising strategy that can be used to improve the therapeutic efficacy, and the identification of precise biomarkers of this combined therapy is the direction of future studies.

The significance of gene mutations across eight major cancer types

Mutations occur spontaneously, which can be induced by either chemicals (e.g. benzene) or biological factors (e.g. virus). Not all mutations cause noticeable changes in cellular functions. However, mutation in key cellular genes leads to developmental disorders. It is one of the main ways in which proto-oncogenes can be changed into their oncogenic state. The progressive accumulation of multiple mutations throughout life leads to cancer. In the past few decades, extensive research on cancer biology has discovered many genes and pathways having role in cancer development. In this review, we tried to summarize the current knowledge of mutational effect on different cancer types and its consequences in brief for future reference and guidance of researchers in cancer biology.

Is There a Role for Preoperative 5 Alpha Reductase Inhibitors in Reducing Prostate Vascularity and Blood Loss?

Benign prostatic hyperplasia (BPH) and the related medical problems are a major burden as health care costs and as a cause of patient morbidity. The introduction of medical therapy largely offered an alternative to surgical therapy, and these medications have been linked with multiple positive BPH-related outcomes. With ubiquitous use, however, a variety of adverse side effects and unsupported claims to these medications have been reported both in scientific literature and popular press. The use of 5 alpha reductase inhibitors (5ARIs) to reduce recurrent bleeding due to BPH is a reasonable option for men with recurrent trips to the physician or hospital. After a largely anecdotal report of their use in the preoperative period to reduce bleeding during BPH surgery, there was interest in the use of 5ARIs for this indication considering the effusive bleeding that can occur during BPH-related surgery, a dreaded and not uncommon complication. While the pathophysiology for the use of 5ARI to reduce BPH-related bleeding is sound, the actual clinical outcomes still require scrutiny to determine if the efficacy is both scientifically valid and clinically significant. This report will review the current literature on this topic and make attempts to determine if the use of a 5ARI before BPH-related surgery should be encouraged.

In Vitro Antitumor Effects of AHR Ligands Aminoflavone (AFP 464) and Benzothiazole (5F 203) in Human Renal Carcinoma Cells

We investigated activity and mechanism of action of two AhR ligand antitumor agents, AFP 464 and 5F 203 on human renal cancer cells, specifically examining their effects on cell cycle progression, apoptosis, and migration. TK-10, SN12C, Caki-1, and ACHN human renal cancer cell lines were treated with AFP 464 and 5F 203. We evaluated cytotoxicity by MTS assays, cell cycle arrest, and apoptosis by flow cytometry and corroborated a mechanism of action involving AhR signal transduction activation. Changes in migration properties by wound healing assays were investigated: 5F 203-sensitive cells show decreased migration after treatment, therefore, we measured c-Met phosphorylation by Western blot in these cells. A 5F 203 induced a decrease in cell viability which was more marked than AFP 464. This cytotoxicity was reduced after treatment with the AhR inhibitor α-NF for both compounds indicating AhR signaling activation plays a role in the mechanism of action. A 5F 203 is sequestered by TK-10 cells and induces CYP1A1 expression; 5F 203 potently inhibited migration of TK-10, Caki-1, and SN12C cells, and inhibited c-Met receptor phosphorylation in TK-10 cells. AhR ligand antitumor agents AFP 464 and 5F 203 represent potential new candidates for the treatment of renal cancer. A 5F 203 only inhibited migration of sensitive cells and c-Met receptor phosphorylation in TK-10 cells. c-Met receptor signal transduction is important in migration and metastasis. Therefore, we consider that 5F 203 offers potential for the treatment of metastatic renal carcinoma. J. Cell. Biochem. 118: 4526-4535, 2017. © 2017 Wiley Periodicals, Inc.

Do programmed death 1 (PD-1) and its ligand (PD-L1) play a role in patients with non-clear cell renal cell carcinoma?

Clinical trials targeting programmed death 1 (PD-1) and its ligand PD-L1 (PD-L1) for metastatic renal cell cancer (RCC) are ongoing. The aim of this study is to validate their roles as prognostic markers in non-clear cell (non-cc) RCC. Sixty-four non-cc RCC tissue specimens were collected from patients undergoing renal tumor surgery. Expressions of biomarkers were assessed using immunohistochemistry and compared with clinical characteristics. Survival analyses were performed with a median follow-up of 77.5 (range: 0-176) months. No significant correlations were found for PD-1(+) tumor-infiltrating mononuclear cells (TIMC) or PD-L1(+) expression and clinical attributes in patients with non-cc RCC. Kaplan-Meier analysis revealed no differences in 5- and 10-year cancer-specific survival (CSS) for PD-1(-) TIMC compared to PD-1(+) TIMC (71.4 and 63 % versus 72.2 and 61.9 %; p = 0.88). Intratumoral expression of PD-L1 did not appear to influence the 5- and 10-year CSS significantly, even though a trend was identified (68 and 53.6 % versus 80.1 and 75.7 %; p = 0.08). In multivariate analysis, neither PD-1(+) TIMC nor intratumoral PD-L1(+) expression proved to be independent predictors of CSS (p = 0.99 and p = 0.68, respectively). Our study demonstrates that PD-1(+) TIMC and intratumoral PD-L1(+) expression did not significantly impact tumor aggressiveness or clinical outcome in non-ccRCC specimens. Due to rare incidence of non-cc RCC in particular according to PD-L1 expression, further analyzes are warranted.

Everolimus versus sunitinib for patients with metastatic non-clear cell renal cell carcinoma (ASPEN): a multicentre, open-label, randomised phase 2 trial

BACKGROUND

Non-clear cell renal cell carcinomas are histologically and genetically diverse kidney cancers with variable prognoses, and their optimum initial treatment is unknown. We aimed to compare the mTOR inhibitor everolimus and the VEGF receptor inhibitor sunitinib in patients with non-clear cell renal cell carcinoma.

METHODS

We enrolled patients with metastatic papillary, chromophobe, or unclassified non-clear cell renal cell carcinoma with no history of previous systemic treatment. Patients were randomly assigned (1:1) to receive everolimus (10 mg/day) or sunitinib (50 mg/day; 6-week cycles of 4 weeks with treatment followed by 2 weeks without treatment) administered orally until disease progression or unacceptable toxicity. Randomisation was stratified by Memorial Sloan Kettering Cancer Center risk group and papillary histology. The primary endpoint was progression-free survival in the intention-to-treat population using the RECIST 1.1 criteria. Safety was assessed in all patients who were randomly assigned to treatment. This study is registered with ClinicalTrials.gov, number NCT01108445.

FINDINGS

Between Sept 23, 2010, and Oct 28, 2013, 108 patients were randomly assigned to receive either sunitinib (n=51) or everolimus (n=57). As of December, 2014, 87 progression-free survival events had occurred with two remaining active patients, and the trial was closed for the primary analysis. Sunitinib significantly increased progression-free survival compared with everolimus (8·3 months [80% CI 5·8-11·4] vs 5·6 months [5·5-6·0]; hazard ratio 1·41 [80% CI 1·03-1·92]; p=0·16), although heterogeneity of the treatment effect was noted on the basis of histological subtypes and prognostic risk groups. No unexpected toxic effects were reported, and the most common grade 3-4 adverse events were hypertension (12 [24%] of 51 patients in the sunitinib group vs one [2%] of 57 patients in the everolimus group), infection (six [12%] vs four [7%]), diarrhoea (five [10%] vs one [2%]), pneumonitis (none vs five [9%]), stomatitis (none vs five [9%]), and hand-foot syndrome (four [8%] vs none).

INTERPRETATION

In patients with metastatic non-clear cell renal cell carcinoma, sunitinib improved progression-free survival compared with everolimus. Future trials of novel agents should account for heterogeneity in disease outcomes based on genetic, histological, and prognostic factors.

FUNDING

Novartis and Pfizer.

A first-in-human study of AMG 208, an oral MET inhibitor, in adult patients with advanced solid tumors

BACKGROUND

This first-in-human study evaluated AMG 208, a small-molecule MET inhibitor, in patients with advanced solid tumors.

METHODS

Three to nine patients were enrolled into one of seven AMG 208 dose cohorts (25, 50, 100, 150, 200, 300, and 400 mg). Patients received AMG 208 orally on days 1 and days 4-28 once daily. The primary objectives were to evaluate the safety, tolerability, pharmacokinetics, and maximum tolerated dose (MTD) of AMG 208.

RESULTS

Fifty-four patients were enrolled. Six dose-limiting toxicities were observed: grade 3 increased aspartate aminotransferase (200 mg), grade 3 thrombocytopenia (200 mg), grade 4 acute myocardial infarction (300 mg), grade 3 prolonged QT (300 mg), and two cases of grade 3 hypertension (400 mg). The MTD was not reached. The most frequent grade ≥3 treatment-related adverse event was anemia (n = 3) followed by hypertension, prolonged QT, and thrombocytopenia (two patients each). AMG 208 exposure increased linearly with dose; mean plasma half-life estimates were 21.4-68.7 hours. One complete response (prostate cancer) and three partial responses (two in prostate cancer, one in kidney cancer) were observed.

CONCLUSIONS

In this study, AMG 208 had manageable toxicities and showed evidence of antitumor activity, particularly in prostate cancer.

Trial Watch: Therapeutic vaccines in metastatic renal cell carcinoma

Despite the renaissance of cancer immunotherapy, no novel immunotherapy has been approved for the treatment of renal cell cancer (RCC) since the availability of recombinant cytokines (interleukin-2, interferon-α). All vaccine trials have failed to meet their endpoints although they have highlighted potential predictive biomarkers (e.g., pre-existing immune response, hematological parameters, tumor burden). Recent advances in immunomodulatory therapies have prompted the study of combination treatments targeting the tumor immunosuppressive microenvironment consisting of regulatory T-cells (Treg), myeloid suppressor cells, and cytokines. Approaches under investigation are use of inhibitors to curb the overexpression of immune checkpoint ligands by tumor cells (e.g., anti-CTLA-4, anti-PD-1/PD-L1) and exploiting the immunomodulatory effects of anti-angiogenic agents that are the current standard of metastatic RCC care. Phase III trials are focusing on the possible synergy between therapeutic vaccines (e.g., IMA-901 and AGS-003) and anti-angiogenic agents.

Genome-Wide Profiling of TRACK Kidneys Shows Similarity to the Human ccRCC Transcriptome

Renal cell carcinoma (RCC) is the most common cancer arising from the kidney in adults, with clear cell RCC (ccRCC) representing the majority of all RCCs. Expression of a human HIF1α triple-mutant (P402A, P564A, and N803A) construct in the proximal tubule cells of C57BL/6 mice [TRAnsgenic model of Cancer of the Kidney (TRACK); ref. 1] mimics the histologic changes found in early stage human ccRCC. To better understand the genomic landscape, a high-throughput sequence analysis was performed with cDNA libraries (RNAseq) derived from TRACK transgenic positive (TG(+)) kidney cortex along with human ccRCC transcripts from the Oncomine and The Cancer Genome Atlas databases. Importantly, the expression profiles of TRACK TG(+) kidneys show significant similarities with those observed in human ccRCC, including increased expression of genes involved in glycolysis and the tricarboxylic acid cycle. Some of the transcripts overexpressed in both the TRACK mouse model and human ccRCC include ANKRD37, CA9, EGLN3, HK2, NDUFA4L2, and SLC16A3. These data suggest that constitutive activation of HIF1α in kidney proximal tubule cells transcriptionally reprograms the regulation of metabolic pathways in the kidney and that HIF1α is a major contributor to the altered metabolism observed in human ccRCC.

IMPLICATIONS

TRACK (GGT-HIF1αM3) kidney mRNA profiles show similarities to human ccRCC transcriptome and phenotypes associated with the Warburg effect.

Clinical behavior of chromophobe renal cell carcinoma is less aggressive than that of clear cell renal cell carcinoma, independent of Fuhrman grade or tumor size

Chromophobe renal cell carcinoma (chRCC) is the third most common subtype of RCC, after clear cell (ccRCC) and papillary RCC. Its lower incidence and frequent exclusion from clinical trials might be why chRCC characteristics have not been extensively studied. The aim of our study was to examine tumor characteristics and long-term prognosis of chRCC compared to ccRCC. We collected 4,210 evaluable patients subjected to surgery for chRCC (n = 176) or ccRCC (n = 4,034) at five centers in Germany (University Hospitals of Hannover, Homburg/Saar, Mainz, Ulm, and Marburg) between 1990 and 2010. Patients with chRCC were significantly younger (mean, 60.1 vs. 62.1 years) and tended to be more frequently female (43.8 vs. 36.5 %). Although Fuhrman grade and median tumor diameter were not significantly different, significantly fewer patients with chRCC than with ccRCC presented with high tumor stage or metastasis at diagnosis (18.5 vs. 43.8 %). Moreover, significantly more chRCC patients were treated with partial nephrectomy (41.5 vs. 26.2 %). Accordingly, 5-year cancer-specific survival (CSS) rates were 83.2 % for chRCC against 75.8 % for ccRCC patients (p = 0.014, log rank). However, in multivariate analysis, chromophobe subtype was not confirmed as a significant positive prognostic factor for RCC (HR 0.88, 95 % CI 0.63-1.24; p = 0.48 Cox regression). This is one of the largest studies to date showing that chRCC is associated with a significantly lower risk of locally invasive tumor growth and metastatic disease than ccRCC. We conclude that the clinical behavior of chRCC is less aggressive than that of ccRCC, independent of Fuhrman grade or tumor size.

Signalling pathways involved in antitumoral effects of VIP in human renal cell carcinoma A498 cells: VIP induction of p53 expression

Vasoactive intestinal peptide (VIP) decreases cell proliferation through PI3K signalling and prevents tumour progression in clear renal cell carcinoma (RCC). Here we analyzed the signalling pathways that mediate such VIP effects by using human RCC A498 cells. The effects of treatment with 1 μM VIP and/or specific protein kinase inhibitors such as H89, Wortmannin and PD98059 were studied by cell adhesion assay, ELISA of VEGF165 and ROS production assays. Semiquantitative RT-PCR and western blot were performed to study p53 expression. VIP increased cell adhesion and ROS production, and decreased VEGF165 secretion through PI3K signalling. Moreover, VIP increased nuclear expression of tumour suppressor p53. VIP effects could be blocked by cell incubation with a specific p53 inhibitor, cyclin pifithrin-α hydrobromide (CPFT-αH). In conclusion, this study provides a p53-dependent mechanism by which VIP regulates cell proliferation in RCC development. It supports a potential usefulness of VIP in new therapies of RCC.

Four individually druggable MET hotspots mediate HGF-driven tumor progression

Activation of MET by HGF plays a key role in tumor progression. Using a recently developed llama platform that generates human-like immunoglobulins, we selected 68 different antibodies that compete with HGF for binding to MET. HGF-competing antibodies recognized 4 distinct hotspots localized in different MET domains. We identified 1 hotspot that coincides with the known HGF β chain binding site on blades 2-3 of the SEMA domain β-propeller. We determined that a second and a third hotspot lie within blade 5 of the SEMA domain and IPT domains 2-3, both of which are thought to bind to HGF α chain. Characterization of the fourth hotspot revealed a region across the PSI-IPT 1 domains not previously associated with HGF binding. Individual or combined targeting of these hotspots effectively interrupted HGF/MET signaling in multiple cell-based biochemical and biological assays. Selected antibodies directed against SEMA blades 2-3 and the PSI-IPT 1 region inhibited brain invasion and prolonged survival in a glioblastoma multiforme model, prevented metastatic disease following neoadjuvant therapy in a triple-negative mammary carcinoma model, and suppressed cancer cell dissemination to the liver in a KRAS-mutant metastatic colorectal cancer model. These results identify multiple regions of MET responsible for HGF-mediated tumor progression, unraveling the complexity of HGF-MET interaction, and provide selective molecular tools for targeting MET activity in cancer.

Aquaporin-1 protein levels elevated in fresh urine of renal cell carcinoma patients: potential use for screening and classification of incidental renal lesions

INTRODUCTION AND OBJECTIVES

There are over 65,000 new cases of renal cell carcinoma (RCC) each year, yet there is no effective clinical screening test for RCC. A single report claimed no overlap between urine levels of aquaporin-1 (AQP1) in patients with and without RCC (Mayo Clin Proc. 85:413, 2010). Here, we used archived and fresh RCC patient urine to validate this report.

METHODS

Archived RCC, fresh prenephrectomy RCC, and non-RCC negative control urines were processed for Western blot analysis. Urinary creatinine concentrations were quantified by the Jaffe reaction (Nephron 16:31, 1976). Precipitated protein was dissolved in 1x SDS for a final concentration of 2  μg/µL creatinine.

RESULTS

Negative control and archived RCC patient urine failed to show any AQP1 protein by Western blot analysis. Fresh RCC patient urine is robustly positive for AQP1. There was no signal overlap between fresh RCC and negative control, making differentiation straightforward.

CONCLUSIONS

Our data confirms that fresh urine of patients with RCC contains easily detectable AQP1 protein. However, archival specimens showed an absence of detectable AQP1 indistinguishable from negative control. These findings suggest that a clinically applicable diagnostic test for AQP1 in fresh urine may be useful for detecting RCC.

Higher circulating expression levels of miR-221 associated with poor overall survival in renal cell carcinoma patients

The mechanisms involved in renal cell carcinoma (RCC) development and progression remain unclear, and new biomarkers for early detection, follow-up of the disease and prognosis are needed in routine practice to improve the diagnostic and/or prognostic accuracy. There is increasing evidence that microRNAs (miRNAs) are involved in cancer development and progression. The up-regulation of miR-221/222 has been described in several human cancers, and during RCC development, this up-regulation can modulate the metastatic process. Our purpose was to investigate the circulating expression levels of miR-221/222 as potential biomarkers for RCC detection and their influence in patients' overall survival. The circulating miR-221/222 was studied by relative quantification in 77 plasma samples. A follow-up study was undertaken to evaluate the overall survival. We observed that RCC patients presented higher circulating expression levels of miR-221 and miR-222 than healthy individuals (2(-ΔΔCt) = 2.8, P = 0.028; 2(-ΔΔCt) = 2.2, P = 0.044, respectively). The RCC patients with metastasis at diagnosis also presented higher circulating expression levels of miR-221 than patients with no metastasis (2(-ΔΔCt) = 10.9, P = 0.001). We also observed a significantly lower overall survival in patients with higher expression levels of miR-221 (48 vs 116 months, respectively; P = 0.024). Furthermore, multivariate Cox regression analysis using the tumour, nodes and metastasis stage (TNM stage); Fuhrman nuclear grade and age (≥60 years) as covariants demonstrated a higher risk of specific death by cancer in patients who presented higher expression levels of miR-221 (hazard ratio (HR) = 10.7, 95% confidence interval 1.33-85.65, P = 0.026). The concordance (c) index showed that the definition of profiles that contain information regarding tumour characteristics associated with circulating miR-221 expression information presents an increased capacity to predict the risk of death by RCC (c index model 1, 0.800 vs model 2, 0.961). Our results, which identified the plasma miR-221/222 at variable levels during RCC development, suggest that these miRNAs may have a potential as noninvasive biomarkers of RCC development.

Proliferation inhibition and the underlying molecular mechanisms of microRNA-30d in renal carcinoma cells

To investigate the inhibitory effects of microRNA-30d (miR-30d) on renal carcinoma cell proliferation and the underlying molecular mechanisms, miR-30d expression in renal cell carcinoma (RCC) specimens was analyzed by quantitative polymerase chain reaction (qPCR). The inhibition of the proliferation of miR-30d on renal carcinoma cells (ACHN cell line) was analyzed by MTT and colony formation assays. The effects of miR-30d on cyclin E2 expression were detected by the luciferase activity of the reporter gene. In addition, the effects of miR-30d on endogenous cyclin E2 expression at the RNA and protein levels were investigated by qPCR and western blot analysis, respectively. Cell cycles were analyzed by flow cytometry. The results showed the following: i) Expression of miR-30d was significantly downregulated in renal carcinoma tissues compared with paraneoplastic tissues; ii) overexpression of miR-30d inhibited renal carcinoma cell proliferation and colony formation; iii) miR-30d inhibited cyclin E2 3' untranslated region-mediated reporter gene expression; and iv) overexpression of miR-30d downregulated endogenous cyclin E2 expression and blocked the cell cycle at the G₁ phase. In conclusion, miR-30d functions as a tumor suppressor gene in RCC and inhibits renal carcinoma cell proliferation. Cell cycle regulatory factor cyclin E2 is a target gene of miR-30d. miR-30d inhibits renal carcinoma cell proliferation via the regulation of cyclin E2 expression at the post-transcriptional level.

Foretinib (XL880): c-MET inhibitor with activity in papillary renal cell cancer

Papillary renal cell cancer (RCC) constitutes approximately 10 % of renal cancers and is the commonest form after clear cell RCC, which accounts for approximately 75 % of cases. Until recently, most clinical trials in RCC were open to patients of all histologic types. Very recent clinical trials have been performed predominately in patients with clear cell RCC and relatively few trials have been done for patients with papillary RCC. The clinical characteristics of papillary RCC are less well appreciated because of both its relative rarity in the general oncology population and the lack of related clinical studies. This article reviews papillary RCC as a clinical entity separate from clear cell RCC. The MET signaling pathway, its association with increased invasion and progression of human cancer, and its dysregulation in papillary RCC is discussed. Lastly, foretinib, a multitargeted receptor tyrosine kinase inhibitor of several receptors, including MET and vascular endothelial growth factor receptor 2, is described in preclinical and phase I studies as well as in a phase II study in papillary RCC patients.

Rare insights into cancer biology

Cancer-associated mutations have been identified in the metabolic genes succinate dehydrogenase (SDH), fumarate hydratase (FH) and isocitrate dehydrogenase (IDH), advancing and challenging our understanding of cellular function and disease mechanisms and providing direct links between dysregulated metabolism and cancer. Some striking parallels exist in the cellular consequences of the genetic mutations within this triad of cancer syndromes, including accumulation of oncometabolites and competitive inhibition of 2-oxoglutarate-dependent dioxygenases, particularly, hypoxia-inducible factor (HIF) prolyl hydroxylases, JmjC domain-containing histone demethylases (part of the JMJD family) and the ten-eleven translocation (TET) family of 5methyl cytosine (5mC) DNA hydroxylases. These lead to activation of HIF-dependent oncogenic pathways and inhibition of histone and DNA demethylation. Mutations in FH, resulting in loss of enzyme activity, predispose affected individuals to a rare cancer, hereditary leiomyomatosis and renal cell cancer (HLRCC), characterised by benign smooth muscle cutaneous and uterine tumours (leiomyomata) and an aggressive form of collecting duct and type 2 papillary renal cancer. Interestingly, loss of FH activity results in the accumulation of high levels of fumarate that can lead to the non-enzymatic modification of cysteine residues in multiple proteins (succination) and in some cases to their disrupted function. Here we consider that the study of rare diseases such as HLRCC, combining analyses of human tumours and cell lines with in vitro and in vivo murine models has provided novel insights into cancer biology associated with dysregulated metabolism and represents a useful paradigm for cancer research.

Influence of survivin (BIRC5) and caspase-9 (CASP9) functional polymorphisms in renal cell carcinoma development: a study in a southern European population

Renal cell carcinoma (RCC) is the most common cancer of the adult kidney and its incidence and mortality has increase in the last 20 years. The disruption of cellular death is one the mechanism involved in cancer development. This process is precise regulated by apoptotic and anti-apoptotic molecules. Survivin (BIRC5) is a member of the inhibitor of apoptosis protein family and has the ability to inhibit the activation of the pro-apoptotic caspase-9 (CASP9). Thus BIRC5 and CASP9 functional polymorphisms might modulate the apoptosis and consequently RCC development. Our purpose was to investigate the potential role of BIRC5-31G/C and CASP9+83C/T functional polymorphisms in the risk for the development of RCC and metastatic disease. We studied the BIRC5-31G/C and CASP9+83C/T functional polymorphisms by PCR-RFLP and allelic discrimination using the 7300 real-time polymerase chain reaction system, respectively, in 178 RCC patients and in 305 healthy individuals. Regarding the BIRC5-31G/C polymorphism, there is a trend to an overrepresentation of CC genotype in RCC group compared with normal controls (aOR, 1.94; P=0.053). We observed, after gender stratification and age-adjustment, that BIRC5-31CC and CASP9+83CT/TT genotypes were associated with an increased risk for RCC development in the female group of our southern European study population (aOR=3.85; P=0.019; aOR=2.98; P=0.028; respectively). Concerning the waiting time for onset of metastatic disease, we observed that BIRC5-31CC homozygous developed metastasis 8 years earlier than the G carriers using a Cox proportional hazard model with gender as covariate (HR=4.9, P=0.038, P bootstrap=0.009). The Cox regression proportional hazard model was validated using bootstrap statistic with 1,000 samples of the same number of patients as the original dataset. Our results suggest that individual differences influence the susceptibility to RCC and tumor behavior. This genetic profile may help to define higher risk groups that would benefit from individualized chemoprevention strategies and therapies.

Clinical applications of recent molecular advances in urologic malignancies: no longer chasing a "mirage"?

As our understanding of the molecular events leading to the development and progression of genitourologic malignancies, new markers of detection, prognostication, and therapy prediction can be exploited in the management of these prevalent tumors. The current review discusses the recent advances in prostate, bladder, renal, and testicular neoplasms that are pertinent to the anatomic pathologist.

Activation of HIF2α in kidney proximal tubule cells causes abnormal glycogen deposition but not tumorigenesis

Renal cell carcinoma (RCC) is the most common primary cancer arising from the kidney in adults, with clear cell renal cell carcinoma (ccRCC) representing approximately 75% of all RCCs. Increased expression of the hypoxia-induced factors-1α (HIF1α) and HIF2α has been suggested as a pivotal step in ccRCC carcinogenesis, but this has not been thoroughly tested. Here, we report that expression of a constitutively activated form of HIF2α (P405A, P530A, and N851A, named as HIF2αM3) in the proximal tubules of mice is not sufficient to promote ccRCC by itself, nor does it enhance HIF1αM3 oncogenesis when coexpressed with constitutively active HIF1αM3. Neoplastic transformation in kidneys was not detected at up to 33 months of age, nor was increased expression of Ki67 (MKI67), γH2AX (H2AFX), or CD70 observed. Furthermore, the genome-wide transcriptome of the transgenic kidneys does not resemble human ccRCC. We conclude that a constitutively active HIF2α is not sufficient to cause neoplastic transformation of proximal tubules, arguing against the idea that HIF2α activation is critical for ccRCC tumorigenesis.

Prolonged efficacy of mTOR inhibitors in papillary renal cell carcinoma: progression-free survival lasting for over 3 years, a case report and review of the literature

Treatment of metastatic renal cell carcinoma has radically changed during the last decade with the approval of new drugs, antiangiogenic agents and mammalian targets of rapamycin (m-TOR) inhibitors. The outcome of metastatic clear-cell carcinoma has been significantly improved, while other entities such as metastatic papillary renal cell carcinoma are still associated with a poor prognosis. To date, there is no standard guideline for metastatic non clear cell carcinoma. We report the case of a 68-year-old patient with a pulmonary metastatic evolution of a papillary kidney cancer who has had more than 3 years disease progression-free survival and is under ongoing treatment with m-TOR inhibitors.

Successful treatment of erythropoietin-producing advanced renal cell carcinoma after targeted therapy using sunitinib: Case report and review of the literature

In general, only ≤5% of patients with renal cell carcinoma (RCC) develop paraneoplastic erythropoietin (EPO) overproduction-induced polycythemia. However, a number of reports on EPO-producing RCC are available. The present study aimed to report the first case of a patient demonstrating a therapeutic effect on EPO-producing advanced RCC, subsequent to targeted pre-surgical sunitinib therapy, with a review of the literature. The patient involved was a 62-year-old male who presented with a malformation of the left scrotum. Examination revealed a tumor of 73 mm in diameter along with lymph node metastasis. The histological examination indicated a clear cell RCC containing viable cells as well as hemorrhage and necrosis. EPO in cancer cells was confirmed by immunohistochemistry. Subsequently, a case of EPO-producing RCC with polycythemia was diagnosed. The EPO-producing RCC was successfully treated following targeted presurgical therapy with sunitinib.

Regulation of mitochondrial oxidative metabolism by tumor suppressor FLCN

BACKGROUND

Birt-Hogg-Dubé (BHD) syndrome is a hereditary hamartoma syndrome that predisposes patients to develop hair follicle tumors, lung cysts, and kidney cancer. Genetic studies of BHD patients have uncovered the causative gene, FLCN, but its function is incompletely understood.

METHODS

Mice with conditional alleles of FLCN and/or peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1A), a transcriptional coactivator that regulates mitochondrial biogenesis, were crossbred with mice harboring either muscle creatine kinase (CKM) -Cre or myogenin (MYOG) -Cre transgenes to knock out FLCN and/or PPARGC1A in muscle, or cadherin 16 (CDH16)- Cre transgenes to knock out FLCN and/or PPARGC1A in kidney. Real-time polymerase chain reaction, immunoblotting, electron microscopy, and metabolic profiling assay were performed to evaluate mitochondrial biogenesis and function in muscle. Immunoblotting, electron microscopy, and histological analysis were used to investigate expression and the pathological role of PPARGC1A in FLCN-deficient kidney. Real-time polymerase chain reaction, oxygen consumption measurement, and flow cytometry were carried out using a FLCN-null kidney cancer cell line. All statistical analyses were two-sided.

RESULTS

Muscle-targeted FLCN knockout mice underwent a pronounced metabolic shift toward oxidative phosphorylation, including increased mitochondrial biogenesis (FLCN ( f/f ) vs FLCN ( f/f ) /CKM-Cre: % mitochondrial area mean = 7.8% vs 17.8%; difference = 10.0%; 95% confidence interval = 5.7% to 14.3%; P < .001), and the observed increase in mitochondrial biogenesis was PPARGC1A dependent. Reconstitution of FLCN-null kidney cancer cells with wild-type FLCN suppressed mitochondrial metabolism and PPARGC1A expression. Kidney-targeted PPARGC1A inactivation partially rescued the enlarged kidney phenotype and abrogated the hyperplastic cells observed in the FLCN-deficient kidney.

CONCLUSION

FLCN deficiency and subsequent increased PPARGC1A expression result in increased mitochondrial function and oxidative metabolism as the source of cellular energy, which may give FLCN-null kidney cells a growth advantage and drive hyperplastic transformation.

Protein profiling of blood samples from patients with hereditary leiomyomatosis and renal cell cancer by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is an extremely rare syndrome with autosomal dominant inheritance. HLRCC is characterized by a predisposition to leiomyomas of the skin and the uterus as well as renal cell carcinoma. The disease-related gene has been identified as fumarate hydratase (fumarase, FH), which encodes an enzyme involved in the mitochondrial tricarboxylic acid cycle. Protein profiling may give some insight into the molecular pathways of HLRCC. Therefore, we performed protein profiling of blood samples from HLRCC patients, their family members, and healthy volunteers, using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) coupled with IMAC-Cu chips. For hierarchical clustering analysis, we used the 45 peaks that revealed significant differences in single-marker analysis over the range from 1500 to 15,000 m/z. Heat map analysis based on the results of clustering distinguished the HLRCC kindred from non-HLRCC subjects with a sensitivity of 94% and a specificity of 90%. SELDI-TOF MS profiling of blood samples can be applied to identify patients with HLRCC and to assess specific molecular mechanisms involved in this condition.

Emerging critical role of molecular testing in diagnostic genitourinary pathology

CONTEXT

The unprecedented advances in cancer genetics and genomics are rapidly affecting clinical management and diagnostics in solid tumor oncology. Molecular diagnostics is now an integral part of routine clinical management in patients with lung, colon, and breast cancer. In sharp contrast, molecular biomarkers have been largely excluded from current management algorithms of urologic malignancies.

OBJECTIVE

To discuss promising candidate biomarkers that may soon make their transition to the realm of clinical management of genitourologic malignancies. The need for new treatment alternatives that can improve upon the modest outcome so far in patients with several types of urologic cancer is evident. Well-validated prognostic molecular biomarkers that can help clinicians identify patients in need of early aggressive management are lacking. Identifying robust predictive biomarkers that will stratify response to emerging targeted therapeutics is another crucially needed development. A compiled review of salient studies addressing the topic could be helpful in focusing future efforts.

DATA SOURCES

A PubMed (US National Library of Medicine) search for published studies with the following search terms was conducted: molecular , prognostic , targeted therapy , genomics , theranostics and urinary bladder cancer , prostate adenocarcinoma , and renal cell carcinoma . Articles with large cohorts and multivariate analyses were given preference.

CONCLUSIONS

Our recent understanding of the complex molecular alterations involved in the development and progression of urologic malignancies is yielding novel diagnostic and prognostic molecular tools and opening the doors for experimental targeted therapies for these prevalent, frequently lethal solid tumors.

MicroRNA-1826 directly targets beta-catenin (CTNNB1) and MEK1 (MAP2K1) in VHL-inactivated renal cancer

The aim of this project is to identify new therapeutic microRNAs (miRNAs) for von Hippel-Lindau (VHL)-inactivated renal cancer cells. We initially identified several potential miRNAs targeting CTNNB1 and MEK1 using several targets scan algorithms. Only miR-1826 was found to target CTNNB1 and MEK1. Therefore, we focused on miRNA-1826 and performed 3' untranslated region (UTR) luciferase assay, functional analyses and association study between miR-1826 expression and renal cancer patient outcomes. miR-1826 expression was significantly lower in renal cancer tissues compared with non-neoplastic areas and lower expression was significantly associated with overall shorter survival and earlier recurrence after radical nephrectomy. Following miR-1826 transfection, 3' UTR luciferase activity and protein expression of beta-catenin and MEK1 were significantly downregulated in renal cancer cells. Introduction of miR-1826 also inhibited renal cancer cell proliferation, invasion and migration. Additionally, miR-1826 promoted apoptosis and G(1) arrest in VHL-inactivated renal cancer cells. Knockdowns of CTNNB1 and MEK1 by small interfering RNAs reproduced the tumor-suppressive effect of miR-1826. Our data suggest that the miR-1826 plays an important role as a tumor suppressor by downregulating beta-catenin and MEK1 in VHL-inactivated renal cancers.

JunB promotes cell invasion and angiogenesis in VHL-defective renal cell carcinoma

Inactivation of the von Hippel-Lindau (VHL) tumor-suppressor gene causes both hereditary and sporadic clear-cell renal-cell carcinoma (ccRCC). Although the best-characterized function of the VHL protein (pVHL) is regulation of hypoxia-inducible factor-α (HIFα), pVHL also controls the development of pheochromocytoma through HIF-independent pathways by regulating JunB. However, it is largely unknown how these pathways contribute to the development and progression of ccRCC. In the present study, we confirmed that JunB was upregulated in VHL-defective ccRCC specimens by immunostaining. Short-hairpin RNA (shRNA)-mediated knockdown of JunB in 786-O and A498 VHL null ccRCC cells suppressed their invasiveness. In addition, JunB knockdown significantly repressed tumor growth and microvessel density in xenograft tumor assays. Conversely, forced expression of wild-type, but not dimerization-defective, JunB in a VHL-restored 786-O subclone promoted invasion in vitro and tumor growth and vessel formation in vivo. Quantitative PCR array analysis revealed that JunB regulated multiple genes relating to tumor invasion and angiogenesis such as matrix metalloproteinase-2 (MMP-2), MMP-9 and chemokine (C-C motif) ligand-2 (CCL2) in 786-O cells. JunB knockdown in these cells reduced the proteolytic activity of both MMPs in gelatin zymography and the amount of CCL2 in the culture supernatant. Moreover, shRNA-mediated knockdown of MMP-2 or inhibition of CCL2 activity with a neutralizing antibody repressed xenograft tumor growth and angiogenesis. Collectively, these results suggest that JunB promotes tumor invasiveness and enhances angiogenesis in VHL-defective ccRCCs.

An antioxidant response phenotype shared between hereditary and sporadic type 2 papillary renal cell carcinoma

Fumarate hydratase (FH) mutation causes hereditary type 2 papillary renal cell carcinoma (PRCC2). The main effect of FH mutation is fumarate accumulation. The current paradigm posits that the main consequence of fumarate accumulation is HIF-α stabilization. Paradoxically, FH mutation differs from other HIF-α stabilizing mutations, such as VHL and SDH mutations, in its associated tumor types. We identified that fumarate can directly up-regulate antioxidant response element (ARE)-controlled genes. We demonstrated that aldo-keto reductase family 1 member B10 (AKR1B10) is an ARE-controlled gene and is up-regulated upon FH knockdown as well as in FH null cell lines. AKR1B10 overexpression is also a prominent feature in both hereditary and sporadic PRCC2. This phenotype better explains the similarities between hereditary and sporadic PRCC2.

Biomarkers to predict response to sunitinib therapy and prognosis in metastatic renal cell cancer

Sunitinib is an orally-administered, multitargeted tyrosine kinase inhibitor. The main targets are vascular endothelial growth factor receptor (VEGFR)-1, VEGFR-2, VEGFR-3, platelet-derived growth factor receptor (PDGFR)-α, and PDGFR-β. Among therapeutic targeting agents, it is the best available in the USA for patients with metastatic renal cell cancer (RCC). Well-constructed clinical trials have led to the worldwide approval of various agents for RCC. However, in clinical practice, it remains difficult to determine the best treatment strategy with these agents. Therefore, the identification of biomarkers to predict response and side-effects and to select optimal dosages is urgently needed. Potential mechanisms of action and resistance need to be understood in order to make accurate predictions. This article briefly reviews candidate biomarkers of sunitinib therapy in terms of clinical variables, genetic factors, and circulating proteins and endothelial cells. Although further validation and implementation is necessary, if validated, biomarkers will help measure the therapeutic response in individual patients and establish treatment strategies for metastatic RCC.