Expression level of vascular endothelial growth factor receptor-2 in radical nephrectomy specimens as a prognostic predictor in patients with metastatic renal cell carcinoma treated with sunitinib

Renal Carcinoma and Angiogenesis: Therapeutic Target and Biomarkers of Response in Current Therapies

Due to the aberrant hypervascularization and the high immune infiltration of renal tumours, current therapeutic regimens of renal cell carcinoma (RCC) target angiogenic or immunosuppressive pathways or both. Tumour angiogenesis plays an essential role in tumour growth and immunosuppression. Indeed, the aberrant vasculature promotes hypoxia and can also exert immunosuppressive functions. In addition, pro-angiogenic factors, including VEGF-A, have an immunosuppressive action on immune cells. Despite the progress of treatments in RCC, there are still non responders or acquired resistance. Currently, no biomarkers are used in clinical practice to guide the choice between the different available treatments. Considering the role of angiogenesis in RCC, angiogenesis-related markers are interesting candidates. They have been studied in the response to antiangiogenic drugs (AA) and show interest in predicting the response. They have been less studied in immunotherapy alone or combined with AA. In this review, we will discuss the role of angiogenesis in tumour growth and immune escape and the place of angiogenesis-targeted biomarkers to predict response to current therapies in RCC.

68Ga-PSMA-11 PET/CT Parameter Correlates with Pathological VEGFR-2/PDGFR-β Expression in Renal Cell Carcinoma Patients

BACKGROUND

Response prediction is necessary for renal cell carcinoma (RCC) tumors. We aim to evaluate parameters derived from ⁶⁸ Ga-PSMA-11 PET/CT images for prediction of pathological VEGFR-2/PDGFR-β expression of primary RCC tumors.

METHODS

Forty-eight RCC patients were retrospectively enrolled with preoperative ⁶⁸ Ga-PSMA-11 PET/CT scan and surgical specimen. Radiological parameters including tumor diameter, mean CT value, and maximal standard uptake value (SUV_max) were derived from PET/CT images and pathological VEGFR-2/PDGFR-β/PSMA expression were identified with immunohistochemistry. Mann-Whitney U test was performed for continuous variables and the chi-square test for categorical variables. ROC was used for determining the effectiveness of preoperative parameters in differentiating VEGFR-2/PDGFR-β expression. Univariate and multivariate logistic regression analyses were performed for significant parameters to predict VEGFR-2 & PDGFR-β co-expression.

RESULTS

Of the 48 tumors, 25 (52.1%) harbored positive VEGFR-2 expression, 28 (58.3%) harbored positive PDGFR-β expression, and 24 (50%) were both VEGFR-2 positive and PDGFR-β positive. SUV_max significantly differed by subgroups of VEGFR-2/PDGFR-β expression (both P < 0.001). SUV_max demonstrated superior performance for differentiating VEGFR-2 & PDGFR-β co-expression (positive vs. negative), with area under the curve 0.87 (95% CI 0.78-0.96, P < 0.001), sensitivity 93% and specificity 78%. Moreover, SUV_max was identified as the significant predictor for VEGFR-2 & PDGFR-β co-expression (odds ratio 4.01, 95% CI 1.99-8.08, P < 0.001). Concordant with radiological findings with ⁶⁸ Ga-PSMA-11 PET/CT, pathological PSMA staining intensity was significantly higher in both VEGFR-2-positive tumor and PDGFR-β-positive tumor (P = 0.009 and P < 0.001, respectively).

CONCLUSION

⁶⁸ Ga-PSMA-11 PET/CT could effectively identify pathological VEGFR-2/PDGFR-β expression of primary RCC tumors, which may help with selection of mRCC patients suitable for TKIs treatment.

[68Ga]Ga-PSMA-11 PET/CT has potential application in predicting tumor HIF-2α expression and therapeutic response to HIF-2α antagonists in patients with RCC

OBJECTIVE

To evaluate the efficacy of parameters derived from [⁶⁸Ga]Ga-PSMA-11 PET/CT images in predicting pathological HIF-2α expression in primary tumors among patients with renal cell carcinoma (RCC).

METHODS

Fifty-three RCC patients with preoperative [⁶⁸Ga]Ga-PSMA-11 PET/CT scans and complete surgical specimens were retrospectively enrolled in this study. Radiographic parameters were obtained from PET/CT images, and immunohistochemistry was used to measure the expression of HIF-2α and PSMA. Continuous variables and categorical variables were analyzed by the Mann-Whitney U test and chi-square test, respectively. ROC analysis was used to test the efficacy of several preoperative parameters in identifying pathological HIF-2α expression. Univariable logistic regression analyses were performed for significant parameters to predict pathological HIF-2α expression in RCC.

RESULTS

Of the 53 tumors, 29 (54.7%) had high expression of HIF-2α. The SUV_max was significantly different in the HIF-2α expression subgroups (p < 0.001). SUV_max emerged as the most significant parameter to differentiate HIF-2α expression subgroups (high vs. low), with the AUC of 0.93 (95% CI 0.85-1.00, p < 0.001), sensitivity of 90%, and specificity of 88%. Furthermore, SUV_max was confirmed as the most significant predictor of HIF-2α expression level by univariable logistic regression model analysis (odds ratio 1.39, 95% CI 1.17-1.65, p < 0.001). Consistent with the radiographic results of [⁶⁸Ga]Ga-PSMA-11 PET/CT, the staining intensity of pathological PSMA was significantly higher in HIF-2α-high-expressing tumors (p = 0.003).

CONCLUSIONS

[⁶⁸Ga]Ga-PSMA-11 PET/CT was superior in identifying pathological HIF-2α expression in primary tumors of RCC patients, demonstrating its potential application in predicting responses to HIF-2α antagonists.

KEY POINTS

• [⁶⁸Ga]Ga-PSMA-11 PET/CT could potentially predict the HIF-2α expression of primary tumors among patients with RCC. • SUV_maxof [⁶⁸Ga]Ga-PSMA-11 PET/CT was the most significant predictor of HIF-2α expression level. • This probability could help predict the therapeutic response of patients with RCC to HIF-2α antagonists.

Cytoreductive Nephrectomy Promoted Abscopal Effect of Camrelizumab Combined With Radiotherapy for Metastatic Renal Cell Carcinoma: A Case Report and Review of the Literature

There is little evidence around Camrelizumab combined with cytoreductive nephrectomy (CN) and radiotherapy (RT) as a treatment option for metastatic renal cell carcinoma (mRCC). The influence of CN on immune responses and the abscopal effect are not well understood. In this paper, we report a case of anti-programmed cell death-1 (PD-1) treated with combined RT once CN reduced the primary tumor burden (TB). This patient also encountered an increased response to targeted radiotherapy after immune resistance. We also observed a macrophage-to-lymphocyte ratio (MLR) peak, which may be correlated with subsequent pseudoprogression after thoracic radiotherapy. Consequently, even with the disease, this patient has remained stable. This peculiar instance suggests there is a need to investigate the underlying mechanisms of CN in promoting the abscopal effect during immunotherapy when combined with RT. It also suggests that there is a need for further investigation into the role of RT in overcoming immune resistance, and the value of MLR in predicting pseudoprogression. We hypothesize that a heavy tumor burden might suppress the abscopal effect, thereby ensuring that CN promotes it. However, radiotherapy may overcome immune resistance during oligoprogression.

PD-L1 and VEGFR-2 expression in synchronous metastatic renal cell carcinoma treated with targeted therapy following cytoreductive nephrectomy

OBJECTIVES

Few studies have independently investigated the population of patients with synchronous metastatic renal cell carcinoma (smRCC). In this study, we evaluated programmed death protein-ligand 1 (PD-L1) and vascular endothelial growth factor receptor 2 (VEGFR-2) expression in primary tumor tissue of smRCC.

METHODS

A total of 96 patients with smRCC who were treated with cytoreductive nephrectomy followed by targeted therapy from January 2006 to January 2013 were identified. PD-L1 and VEGFR-2 expression were evaluated by immunohistochemistry. Kaplan-Meier and Cox methods were used for analysis.

RESULTS

PD-L1 and VEGFR-2 protein immunopositivity were observed in 39.6% (38 of 96) and 58.3% (56 of 96) of patients, respectively. A significant correlation was detected between VEGFR-2 and PD-L1 expression (P = 0.030). Based on PD-L1 and VEGFR-2 expression, patients with intermediate-risk disease (n = 63) were divided into 4 subgroups including patients who were PD-L1 (+) VEGFR-2 (+) (n = 21), PD-L1 (+) VEGFR-2 (-) (n = 11), PD-L1 (-) VEGFR-2 (+) (n = 15) and PD-L1 (-) VEGFR-2 (-) (n = 16). Compared to the PD-L1 (-) VEGFR-2 (+), PD-L1 (+) VEGFR-2 (+) and PD-L1 (-) VEGFR-2 (-) groups, patients in the PD-L1 (+) VEGFR-2 (-) group had shorter progression-free survival (median, 9.0 vs. 20.0, 16.0 and 15.5 months, P < 0.05) and overall survival (median, 14.0 vs. 33.0, 24.0 and 26.5 months, P < 0.05).

CONCLUSIONS

Intermediate-risk smRCC patients with PD-L1-positive and VEGFR-2-negative expression who were treated with targeted therapy following cytoreductive nephrectomy had poor prognoses. We suggest that other treatments beyond sunitinib or sorafenib may be explored in this subgroup.

Prospective Translational Study Investigating Molecular PrEdictors of Resistance to First-Line PazopanIb in Metastatic reNal CEll Carcinoma (PIPELINE Study)

OBJECTIVES

Despite the initial clinical benefit, resistance to antiangiogenic therapies develops through the activation of alternative pathways. We measured plasma levels of circulating angiogenic factors to explore their predictive role in metastatic renal cell carcinoma (mRCC) patients treated with pazopanib.

MATERIALS AND METHODS

mRCC patients receiving first-line pazopanib were prospectively enrolled. The levels of circulating interleuchine (IL)-6, IL-8, stromal derived factor-1, vascular endothelial growth factor-A, hepatocyte growth factor (HGF), osteopontin, and E-selectin were quantified at baseline and every 4 weeks until disease progression (PD). Patients were dichotomized into "low" and "high" subgroups by a cutoff point defined by the respective median circulating angiogenic factor (CAF) value at baseline. Then, association with the objective response was determined. Changes in CAF levels between baseline and PD were also compared.

RESULTS

Among 25 patients included in the final data set, 6 patients were still on treatment. As best response, 12 patients presented a partial response (48%), 9 showed stable disease, and 4 showed PD. The median follow-up was 31.9 months. The median progression-free survival was 14.8 months. Low baseline levels of IL-6, IL-8, HGF, and osteopontin were found to be significantly associated with objective response. In addition, patients with low baseline levels of HGF showed longer progression-free survival and overall survival, whereas patients with low baseline levels of IL-8 showed longer overall survival. Among patients experiencing PD, the median plasma levels of stromal derived factor-1 and vascular endothelial growth factor-A were significantly higher compared with the baseline (P=0.01; P=0.011). Conversely, the median levels of E-selectin were significantly lower compared with the baseline (P=0.017).

CONCLUSION

Changes in levels of selected CAFs were associated with response/resistance to pazopanib in mRCC patients.

Efficacy and safety of apatinib monotherapy in metastatic renal cell carcinoma (mRCC) patients: A single-arm observational study

BACKGROUND

Antiangiogenic treatments play an important role in the therapeutic strategy for metastatic renal cell carcinoma. Apatinib is an oral tyrosine kinase inhibitor that targets vascular endothelial growth factor receptor-2. We aimed to assess the efficacy and safety of apatinib therapy in metastatic renal cell carcinoma patients.

METHODS

Between January 2018 and November 2018, we enrolled 53 metastatic renal cell carcinoma patients. Apatinib was administered at an initial dose of 500 mg once daily. The disease control rate, objective response rate, progression-free survival, and adverse events were reviewed and evaluated.

FINDINGS

Among the 53 patients, 14 achieved partial response and 31 achieved stable disease. Thus, the disease control rate was 84.9% and the objective response rate was 26.4%. The median progression-free survival was 11.2 months (95% confidence interval: 9.884-12.574). Most of the adverse events (AEs) were at grade 1 or 2, and the main grade 3 AEs were hypertension (5.7%), anemia (3.8%), and thrombocytopenia (3.8%).

INTERPRETATION

Apatinib showed promising efficacy and manageable toxicity in metastatic renal cell carcinoma patients, giving potent evidence to conduct further clinical trials.

Renal Cell Carcinoma in the Era of Precision Medicine: From Molecular Pathology to Tissue-Based Biomarkers

Renal cell carcinoma (RCC) is not a single entity but includes various tumor subtypes that have been identified on the basis of either characteristic pathologic features or distinctive molecular changes. Clear cell RCC is the most common type of RCC and is characterized by dysregulation of the von Hippel Lindau/hypoxia-inducible factor pathway. Non-clear cell RCC represents a more heterogeneous group of tumors with diverse histopathologic and molecular features. In the past two decades, the improved understanding of the molecular landscape of RCC has led to the development of more effective therapies for metastatic RCC, which include both targeted agents and immune checkpoint inhibitors. Because only subsets of patients with metastatic RCC respond to a given treatment, predictive biomarkers are needed to guide treatment selection and sequence. In this review, we describe the key histologic features and molecular alterations of RCC subtypes and discuss emerging tissue-based biomarkers of response to currently available therapies for metastatic disease.

Pro-angiogenic gene expression is associated with better outcome on sunitinib in metastatic clear-cell renal cell carcinoma

OBJECTIVES

Clear-cell renal cell carcinomas (ccRCC) are characterized by hyper-vascularization and can respond to vascular endothelial growth factor receptor (VEGFR) inhibitors such as sunitinib. We aimed to study the predictive value of the expression of genes in the hypoxia induced factor (HIF) - vascular endothelial growth factor (VEGF) - VEGFR-pro-angiogenic pathway in metastatic ccRCC (m-ccRCC) patients treated with sunitinib and the correlation between the expression of these genes and the molecular ccrcc-classification, the expression of genes involved in the immune-suppressive microenvironment and Von Hippel-Lindau (VHL) - and Polybromo-1 (PBRM1) - mutational status.

MATERIAL AND METHODS

m-ccRCC patients treated with sunitinib as first-line targeted therapy were included. Gene expression was studied in the primary nephrectomy sample by qRT-PCR, VHL- and PBRM1-mutational status by sequencing. Response rate by RECIST, progression-free survival (PFS) and overall survival (OS) were study endpoints.

RESULTS

One hundred and four patients were included. On multivariate-analysis, HIF2A-, platelet derived growth factor receptor beta (PDGFRB)-, VEGFC-, VEGFR1- and VEGFR2-expression were correlated with PFS and HIF1A-, HIF2A-, VEGFR1- and VEGFR2-expression with OS. VEGFR2-expression showed the strongest association with outcome, being significantly correlated with all outcome parameters. HIF2A, VEGFA, VEGFR1, VEGFR2 and VEGFR3 were highly expressed in the transcriptomic ccrcc2-subtype of tumors, known to be highly sensitive to sunitinib. In the total tumor series, there was no correlation nor inverse correlation between the expression of genes involved in angiogenesis and in the immune-suppressive microenvironment. In tumors with a bi-allelic PBRM1-inactivation, HIF2A-, VEGFA-, VEGFR1- and VEGFR2-expression were higher, compared to tumors with one or two functional PBRM1-alleles.

CONCLUSIONS

Intratumoral expression of genes involved in the HIF-VEGF-VEGFR-pro-angiogenic pathway, especially VEGFR2, is associated with favorable outcome on sunitinib in m-ccRCCs. Several genes involved in this pathway are upregulated in the molecular ccrcc2-subgroup, which usually responds well to sunitinib.

Prognostic and Predictive Factors for Renal Cell Carcinoma

Metastatic renal cell carcinoma (mRCC) is an incurable malignancy, characterized by its resistance to traditional chemotherapy, radiation, and hormonal therapy. Treatment perspectives and prognosis of patients with mRCC have been significantly improved by advances in the understanding of its molecular pathogenesis, which have led to the development of targeted therapeutics. Different molecular factors derived from the tumor or the host detected in both tissue or serum could be predictive of therapeutic benefit. Some of them suggest a rational selection of patients to be treated with certain therapies, though none have been validated for routine use. This article provides an overview of both clinical and molecular factors associated with predictive or prognostic value in mRCC and emphasizes that both should be considered in parallel to provide the most appropriate, individualized treatment and achieve the best outcomes in clinical practice.

Tumour cell expression of interleukin 6 receptor α is associated with response rates in patients treated with sunitinib for metastatic clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most common type of renal cell carcinoma, and anti‐angiogenic treatment is currently first line therapy for metastatic ccRCC (mccRCC). Response rates and duration of response show considerable variation, and adverse events have a major influence on patient quality of life. The need for predictive biomarkers to select responders to receptor tyrosine kinase inhibitors upfront is urgent. We investigated the predictive value of immunohistochemical biomarkers associated with angiogenesis and systemic inflammation in mccRCC. Forty‐six patients with metastatic or non‐resectable ccRCC treated with sunitinib were included. Metastatic and/or primary tumour tissue was stained by immunohistochemistry for selected markers related to angiogenesis [vascular endothelial growth factor A (VEGF‐A), VEGF receptor 2 (VEGFR2), platelet‐derived growth factor receptor β (PDGFRβ), and heat shock protein 27 (HSP27)] and immune responses [Interleukin 6 receptor α (IL6Rα), interleukin‐6 (IL6), and jagged1 (JAG1)]. The predictive potential of the candidate markers was assessed by correlations with response rates (RECIST). In addition, progression free survival (PFS) and overall survival (OS) were analysed. Low tumour cell expression of IL6Rα was significantly associated with improved response to sunitinib (Fisher's exact test, p = 0.03), but not with PFS or OS. Median/high expression of IL6Rα showed significant association with median/high expression of VEGF‐A and HSP27. Furthermore, low expression of IL6 was significantly associated with improved PFS, but not OS or response rates. High expression of IL6 was significantly associated with high expression of JAG1, VEGF‐A, VEGFR2, and PDGFRβ. Loss of tumour cell expression of IL6Rα in mccRCC patients treated with sunitinib predicts improved treatment response, and might represent a candidate predictive marker.

Effect of Targeting Clusterin Using OGX-011 on Antitumor Activity of Temsirolimus in a Human Renal Cell Carcinoma Model

BACKGROUND

It has not been well documented that the modulation of stress response mediates the efficacy of the mammalian target of rapamycin (mTOR) inhibitor in renal cell carcinoma (RCC).

OBJECTIVE

The objective of this study was to investigate whether the activity of the mTOR inhibitor temsirolimus against RCC could be enhanced by OGX-011, an antisense oligodeoxynucleotide (ODN) targeting the stress-activated chaperone clusterin.

METHODS

We investigated the efficacy of combined treatment with temsirolimus plus OGX-011 in a human RCC Caki-1 model focusing on the effects on apoptotic and autophagic pathways.

RESULTS

Although clusterin expression was increased by temsirolims, additional treatment of Caki-1 with OGX-011 significantly inhibited clusterin upregulation (p < 0.05). Combined treatment of temsirolimus and OGX-011 synergistically enhanced the sensitivity of Caki-1 to temsirolimus (p < 0.01), reducing the IC₅₀ by approximately 50 %. Apoptotic changes were marked in Caki-1 following combined treatment with a sublethal dose of temsirolimus and OGX-011, accompanying the significant downregulation of Mcl-1 (p < 0.05), but not with either agent alone. Furthermore, this combined treatment markedly blocked the temsirolimus-induced activation of autophagy in Caki-1 (p < 0.01). In-vivo systemic administration of temsirolimus plus OGX-011 significantly inhibited the growth of Caki-1 tumors compared with that of temsirolimus plus control ODN (p < 0.05).

CONCLUSIONS

Silencing of clusterin using OGX-011 resulted in the further enhancement of proapoptotic activity as well as the marked attenuation of the autophagic pathway induced by temsirolimus in a human RCC model. Thus, the combined use of OGX-011 could be a promising strategy through the enhanced cytotoxic activity of temsirolimus against RCC.

The effect of apatinib in the treatment of metastatic renal cell carcinoma: a case report and review of the literature

The aim of this study was to explore the effect of apatinib in the treatment of metastatic renal cell carcinoma (mRCC) and related adverse events. A case of mRCC was reported which recurred after surgery and roferon treatment. The patient was treated with apatinib at a dose of 500 mg orally, twice daily, 28 days/cycle. The metastatic lesions improved based on computed tomography after apatinib administration in the fourth and eighth month. The progression-free survival of the patient had increased almost to 8 months. The patient showed a good tolerance with only an adverse effect of mild-to-moderate hand-foot syndrome which was managed well. Apatinib is an option for mRCC after previous treatment. However, more and larger trials are still needed.

Tyrosine kinase inhibitor sunitinib therapy is effective in the treatment of bone metastasis from cancer of unknown primary: Identification of clinical and immunohistochemical biomarkers predicting survival

Bone metastasis from cancer of unknown primary (BMCUP) brings poor survival prognosis and its management remains controversial. Sunitinib (SUTENT) proved effective in many sorts of solid tumors but has never been applied for patients with occult primary cancers, and there is no study to identify sensitive or resistant biomarkers for sunitinib therapy in CUP patients. An analysis was carried out to investigate the efficacy of sunitinib by multivariate survival analysis of 286 patients with BMCUP. We further carried out multivariate analysis to identify histological and clinical biomarkers that could predict sensitivity or resistance for sunitinib therapy. Of the 286 patients included from January 2011 to March 2016, sunitinib therapy proved effective to prolong survival in patients with BMCUP. Sensitive and resistant biomarkers were identified in histological specimen of patients receiving sunitinib therapy. Clinical factors were also identified that predict poor survival prognosis for sunitinib therapy. Sunitinib therapy proved effective to prolong survival in patients with BMCUP. Sensitive markers for sunitinib therapy include KDR positivity and early-developed treatment-induced hypertension. Resistance factors for sunitinib include VEGF positivity, CAIX positivity and squamous cell carcinoma pathology type. Prolonged symptom time and severe weight loss before therapy seemed to be associated with poor survival prognosis for sunitinib therapy.

Target molecule expression profiles in metastatic renal cell carcinoma: Development of individual targeted therapy

The aim of this study is to analyze the level of target molecule expression in metastatic renal cell carcinoma (RCC) to determine whether there is a correlation between molecular marker expression and clinical response. Ten patients with metastatic RCC, who received receptor tyrosine kinase (RTK) targeted therapy after cytoreductive or radical nephrectomy, were included. The expression of target molecules relating to the RTK, mammalian target of rapamycin, hypoxia inducible factor, mitogen activated protein kinase, and adenosine monophosphate-activated protein kinase pathways were analyzed using real-time polymerase chain reaction and immunohistochemistry. We correlated the level of target molecule expression with clinical response, including efficacy and adverse events experience during RTK targeted therapy. All patients showed similar histological subtype and grade on pathological examination; however, the expression of RCC target molecules was very different among the patients. The expression of molecules related to the RTK pathway in RCC tissue as well as relative expression of molecules in RCC tissue compared to normal kidney tissue, were higher in patients who showed a good response to RTK targeted therapy compared to those that showed a poor response. Target molecule expression in normal kidney tissue was higher in patients who experienced high-grade adverse events than in patients who experienced low-grade events. Target molecule expression in metastatic RCC correlates with targeted therapy clinical response including efficacy and adverse events. Personalized target molecule expression profiles could be used to predict clinical response to different targeted therapies, thus helping optimization of targeted therapies for patients with metastatic RCC.

Predictive Immunohistochemical Markers Related to Drug Selection for Patients Treated with Sunitinib or Sorafenib for Metastatic Renal Cell Cancer

Targeted drug decisions in metastatic renal cell carcinoma are exclusively made on the basis of clinical criteria. We investigated whether these biomarkers (HIF-1α, HIF-2α, CAIX, VEGF, VEGFR1, VEGFR2, VEGFR3, PDGFB, PDGFRA, PDGFRB, CD31, CD44, bcl-xL, KIT, p21, CXCR4, PTEN, (CSF)-1R, RET, and FLT-3) can predictive the different effects between sunitinib and sorafenib treatments and are available to guide targeted drug selection. We enrolled all patients who underwent nephrectomy with postoperative sunitinib- or sorafenib-treatment at our institution from 2007 to 2012. Immunohistochemical approach was applied to assess the potential differential effects of immunostainings between sunitinib- and sorafenib-treated groups. We found that patients with high HIF-2α, CD31 expression showed greater relative PFS and OS benefit and patients with high CAIX expression presented greater relative OS benefit from sunitinib than from sorafenib, patients with high VEGFR1 or PDGFRB expression levels exhibited worse relative PFS benefit from sunitinib than from sorafenib. Namely high HIF-2α, CD31, and CAIX expression levels along with low VEGFR1 and PDGFRB expression levels improved the benefit of sunitinib treatment compared with sorafenib treatment. These results can identify whether patients can benefit more from sunitinib or sorafenib for drug selection guidance, eventually with precision medicine.

Analyses of Potential Predictive Markers and Response to Targeted Therapy in Patients with Advanced Clear-cell Renal Cell Carcinoma

Background:

Vascular endothelial growth factor-targeted agents are standard treatments in advanced clear-cell renal cell carcinoma (ccRCC), but biomarkers of activity are lacking. The aim of this study was to investigate the association of Von Hippel-Lindau (VHL) gene status, vascular endothelial growth factor receptor (VEGFR) or stem cell factor receptor (KIT) expression, and their relationships with characteristics and clinical outcome of advanced ccRCC.

Methods:

A total of 59 patients who received targeted treatment with sunitinib or pazopanib were evaluated for determination at Cancer Hospital and Institute, Chinese Academy of Medical Sciences between January 2010 and November 2012. Paraffin-embedded tumor samples were collected and status of the VHL gene and expression of VEGFR and KIT were determined by VHL sequence analysis and immunohistochemistry. Clinical-pathological features were collected and efficacy such as response rate and Median progression-free survival (PFS) and overall survival (OS) were calculated and then compared based on expression status. The Chi-square test, the Kaplan–Meier method, and the Lon-rank test were used for statistical analyses.

Results:

Of 59 patients, objective responses were observed in 28 patients (47.5%). The median PFS was 13.8 months and median OS was 39.9 months. There was an improved PFS in patients with the following clinical features: Male gender, number of metastatic sites 2 or less, VEGFR-2 positive or KIT positive. Eleven patients (18.6%) had evidence of VHL mutation, with an objective response rate of 45.5%, which showed no difference with patients with no VHL mutation (47.9%). VHL mutation status did not correlate with either overall response rate (P = 0.938) or PFS (P = 0.277). The PFS was 17.6 months and 22.2 months in VEGFR-2 positive patients and KIT positive patients, respectively, which was significantly longer than that of VEGFR-2 or KIT negative patients (P = 0.026 and P = 0.043).

Conclusion:

VHL mutation status could not predict the efficacy of sunitinib or pazopanib. Further investigation of VHL/VEGFR pathway components is needed.

Prognostic Biomarkers for Response to Vascular Endothelial Growth Factor-Targeted Therapy for Renal Cell Carcinoma

Improved understanding of renal carcinoma disease biology has led to the discovery and approval of five novel therapies targeting specific molecules in the vascular endothelial growth factor (VEGF) biochemical pathway. Biomarker studies attempting to predict response to VEGF-targeted therapies have largely focused on circulating proteins, tissue-based molecules, and germline polymorphisms. Thus far studies have yielded conflicting results that require prospective validation; therefore no definitive biomarker has yet been integrated into the clinician's armamentarium. However, early analyses featuring genomic biomarkers have generated promising findings. This article provides an overview of available biomarkers evaluated with respect to VEGF-targeted therapies in patients with advanced renal cell carcinoma.

miR-221/222 Are Involved in Response to Sunitinib Treatment in Metastatic Renal Cell Carcinoma

Sunitinib is a multitargeting tyrosine kinase inhibitor used for metastatic renal cancer. There are no biomarkers that can predict sunitinib response. Such markers are needed to avoid administration of costly medication with side effects to patients who would not benefit from it. We compared global miRNA expression between patients with a short (≤12 months) versus prolonged (>12 months) progression-free survival (PFS) under sunitinib as first-line therapy for metastatic renal cell carcinoma. We identified a number of differentially expressed miRNAs and developed miRNA statistical models that can accurately distinguish between the two groups. We validated our models in the discovery set and an independent set of 57 patients. Target prediction and pathway analysis showed that these miRNAs are involved in vascular endothelial growth factor (VEGF), TGFβ, and mammalian target of rapamycin (mTOR)-mediated signaling and cell-cell communication. We tested the effect of these miRNAs on cellular proliferation and angiogenesis. We validated the negative correlation between miR-221 and its target, VEGFR2.miR-221 overexpression was associated with a poor PFS while its target, VEGFR2 was associated with longer survival. Gain of function experiments showed that miR-221 and miR-222 decreased angiogenesis and cellular proliferation in human umbilical vein endothelial cells (HUVEC) while increasing cellular proliferation in ACHN cells. miRNAs represent potential predictive markers for sunitinib response.

Predictive molecular biomarkers to guide clinical decision making in kidney cancer: current progress and future challenges

Although the past decade has seen a surfeit of new targeted therapies for renal cell carcinoma (RCC), no predictive molecular biomarker is currently used in routine clinical practice to guide personalized therapy as a companion diagnostic. Many putative biomarkers have been suggested, but none have undergone rigorous validation. There have been considerable advances in the biological understanding of RCC in recent years, with the development of accompanying molecular diagnostics that with additional validation, may be helpful for routine clinical decision making. In this review, we summarize the current understanding of predictive biomarkers in RCC management and also highlight upcoming developments of interest in biomarker research for personalizing RCC diagnostics and therapeutics.

Resistance to sunitinib in renal cell carcinoma: From molecular mechanisms to predictive markers and future perspectives

The introduction of agents that inhibit tumor angiogenesis by targeting vascular endothelial growth factor (VEGF) signaling has made a significant impact on the survival of patients with metastasized renal cell carcinoma (RCC). Sunitinib, a tyrosine kinase inhibitor of the VEGF receptor, has become the mainstay of treatment for these patients. Although treatment with sunitinib substantially improved patient outcome, the initial success is overshadowed by the occurrence of resistance. The mechanisms of resistance are poorly understood. Insight into the molecular mechanisms of resistance will help to better understand the biology of RCC and can ultimately aid the development of more effective therapies for patients with this infaust disease. In this review we comprehensively discuss molecular mechanisms of resistance to sunitinib and the involved biological processes, summarize potential biomarkers that predict response and resistance to treatment with sunitinib, and elaborate on future perspectives in the treatment of metastasized RCC.

Predictive biomarkers in renal cell cancer: insights in drug resistance mechanisms

INTRODUCTION

VEGF-targeted therapy is currently the first line treatment for patients with metastatic clear cell renal cell carcinoma (ccRCC), but most patients either display primary (intrinsic) resistance or acquire drug resistance. In recent years multiple mechanisms of resistance to VEGF-targeted therapy emerged from preclinical research, but it is currently unknown to what extent these drug resistance modalities play a role in the clinic. Here we reviewed the current literature on biomarkers that predict treatment outcome in patients with ccRCC to gain insight in clinical drug resistance mechanisms.

METHODS

A search syntax was compiled by combining different synonyms of "biomarker" AND "renal" AND "cancer". MEDLINE was accessed through PubMed, where this syntax was entered and used to search titles and abstracts of publications. Articles were selected based on three criteria: (1) description of patients with clear cell RCC, (2) treatment with VEGF targeted therapy and (3) discussion of biomarkers that were studied for potential association with treatment response.

RESULTS

The literature search was performed on March 4th 2014 and yielded 1882 articles. After carefully reading the titles and abstracts based on the three previously mentioned criteria, 103 publications were evaluated. Backward citation screening was performed on all eligible studies and revealed another 24 articles. This search revealed that (1) High glucose uptake and low contrast enhancement on PET- and CT-imaging before start of treatment may correlate with poor response to therapy, (2) Low dose intensity due to treatment intolerance is related to shorter progression free survival. (3) Acquired resistance appears to be associated with rebound vascularization based on both longitudinal monitoring of contrast enhancement by CT and blood vessel counts in tumor tissue, and (4) Based on plasma cytokine and single nucleotide polymorphism (SNP) studies, interleukin-8, VEGFR-3, FGFR2 and HGF/MET emerged as potential clinical markers for chemoresistance.

CONCLUSION

Low dose intensity, specific tumor-imaging techniques and potential biological biomarkers may be predictive for response to VEGF-targeted therapy in ccRCC. Some of these plausible biomarkers may also provide more insight into the underlying mechanisms of resistance such as altered glucose metabolism and rapid rebound vascularization.

Targeted contrast-enhanced ultrasound imaging of angiogenesis in an orthotopic mouse tumor model of renal carcinoma

Previous studies have reported that microbubbles bearing targeting ligands to molecular markers of angiogenesis can be successfully detected by ultrasound imaging in various animal models of solid cancer. In the present study, we sought to investigate the activity of microbubbles targeted to vascular endothelial growth factor receptor 2 (VEGFR2) in an orthotopic model of renal cell carcinoma (RCC). Microbubbles conjugated to an anti-VEGFR2 antibody (MBV) were compared with microbubbles conjugated to an isotype control antibody (MBC) or naked microbubbles (MBN). An orthotopic mouse model of human RCC was established by surgically implanting an established tumor within the renal capsule in mice. Tumor growth and blood flow were verified by B-mode and color Doppler ultrasound imaging. VEGFR2 expression within the tumor and renal parenchyma was detected by immunohistochemistry. The duration of contrast enhancement of MBV was much longer than those of MBN and MBC when assessed over 10 min. The baseline-subtracted contrast intensity within the tumor was higher for MBV than for MBC and MBN (p < 0.01). Additionally, the contrast intensity for MBV was significantly higher in the tumor region than in normal parenchyma (p < 0.01). Microbubbles targeting VEGFR2 exhibit suitable properties for imaging angiogenesis in orthotopic models of renal cell carcinoma, with potential applications in life science research and clinical medicine.

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

Background:

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

Methods:

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

Results:

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

Conclusions:

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

Significance of circulating matrix metalloproteinase-9 to tissue inhibitor of metalloproteinases-2 ratio as a predictor of disease progression in patients with metastatic renal cell carcinoma receiving sunitinib

OBJECTIVES

To assess the significance of circulating matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) as predictors of disease progression in patients with metastatic renal cell carcinoma (mRCC) receiving sunitinib.

MATERIALS AND METHODS

Circulating levels of MMP-2, MMP-9, TIMP-1, and TIMP-2 in sera from 52 patients with mRCC treated with sunitinib were measured at the baseline and on the first day of each treatment cycle until progression using enzyme-linked immunosorbent assays.

RESULTS

The baseline level of MMP-9 in nonresponders to sunitinib was significantly higher than that in responders, whereas the baseline level of TIMP-2 in nonresponders was significantly lower than that in responders. However, there were no significant differences in the serum levels of MMP-2 and TIMP-1 between responders and nonresponders. The serum MMP-9/TIMP-2 ratio at the baseline in nonresponders was also significantly higher than that in responders. Univariate analysis showed that the MMP-9/TIMP-2 ratio, but not MMP-9 and TIMP-2 levels, was significantly correlated with progression-free survival, and the MMP-9/TIMP-2 ratio, in addition to the Memorial Sloan-Kettering Cancer Center classification and C-reactive protein level, appeared to be independently associated with progression-free survival on multivariate analysis. Furthermore, despite the lack of significant differences in the serum levels of MMP-9 and TIMP-2 between the baseline and the time of progression, the MMP-9/TIMP-2 ratio at the time of progression was significantly elevated compared with the baseline ratio.

CONCLUSIONS

An imbalance between the serum MMP-9 and TIMP-2 levels could be a novel biomarker to predict disease progression in patients with mRCC under treatment with sunitinib.

A systematic review of predictive and prognostic biomarkers for VEGF-targeted therapy in renal cell carcinoma

BACKGROUND

Vascular endothelial growth factor (VEGF)-targeted therapy is the currently standard treatment for advanced and metastatic renal cell carcinoma (RCC). Multiple candidate predictive and prognostic biomarkers have been evaluated. We performed a systematic review and graded the available evidence on the biomarkers for VEGF-targeted therapy in RCC.

METHODS

We conducted an independent review of PubMed and ASCO databases up to August 2013. Studies were included if biomarkers obtained from metastatic clear-cell RCC patients treated with the FDA-approved VEGF-targeted therapy were assessed for their correlation with clinical outcomes. We graded the studies and determined the Level-of-evidence for each biomarker using a previously published framework.

RESULTS

A total of 50 articles were selected for this review. Seven studies assessed the predictive value of biomarkers using the archived specimens from randomized controlled trials. Five predictive biomarkers, such as VEGF, interleukin (IL)-6, hepatocyte growth factor (HGF), osteopontin, single nucleotide polymorphisms in IL-8, satisfied Level II evidence. IL-6 is the most corroborated predictive biomarker based on its consistent predictive value in two different trials. The prognostic value of biomarkers was assessed in 48 studies using the archived specimens from clinical trials, prospective and retrospective observational registries. Three biomarkers, including IL-8, HGF and osteopontin, satisfied Level I evidence for PFS.

CONCLUSION

Though several promising predictive biomarkers for VEGF-targeted therapy have been found, none of them has satisfied the determination of Level I evidence. A more focused development of biomarkers with prospective assessment in clinical trials and clear intent of use in clinical practice is needed.

Analyses of potential predictive markers and survival data for a response to sunitinib in patients with metastatic renal cell carcinoma

BACKGROUND

Patients with metastatic clear cell renal cell carcinoma (ccRCC) are frequently treated with tyrosine kinase inhibitors (TKI) such as sunitinib. It inhibits angiogenic pathways by mainly targeting the receptors of VEGF and PDGF. In ccRCC, angiogenesis is characterized by the inactivation of the von Hippel-Lindau gene (VHL) which in turn leads to the induction of HIF1α target genes such as CA9 and VEGF. Furthermore, the angiogenic phenotype of ccRCC is also reflected by endothelial markers (CD31, CD34) or other tumor-promoting factors like Ki67 or survivin.

METHODS

Tissue microarrays from primary tumor specimens of 42 patients with metastatic ccRCC under sunitinib therapy were immunohistochemically stained for selected markers related to angiogenesis. The prognostic and predictive potential of theses markers was assessed on the basis of the objective response rate which was evaluated according to the RECIST criteria after 3, 6, 9 months and after last report (12-54 months) of sunitinib treatment. Additionally, VHL copy number and mutation analyses were performed on DNA from cryo-preserved tumor tissues of 20 ccRCC patients.

RESULTS

Immunostaining of HIF-1α, CA9, Ki67, CD31, pVEGFR1, VEGFR1 and -2, pPDGFRα and -β was significantly associated with the sunitinib response after 6 and 9 months as well as last report under therapy. Furthermore, HIF-1α, CA9, CD34, VEGFR1 and -3 and PDGRFα showed significant associations with progression-free survival (PFS) and overall survival (OS). In multivariate Cox proportional hazards regression analyses high CA9 membrane staining and a response after 9 months were independent prognostic factors for longer OS. Frequently observed copy number loss and mutation of VHL gene lead to altered expression of VHL, HIF-1α, CA9, and VEGF.

CONCLUSIONS

Immunoexpression of HIF-1α, CA9, Ki67, CD31, pVEGFR1, VEGFR1 and -2, pPDGFRα and -β in the primary tumors of metastatic ccRCC patients might support the prediction of a good response to sunitinib treatment.

MicroRNA expression profiling of peripheral blood samples predicts resistance to first-line sunitinib in advanced renal cell carcinoma patients

Anti-angiogenic therapy benefits many patients with advanced renal cell carcinoma (RCC), but there is still a need for predictive markers that help in selecting the best therapy for individual patients. MicroRNAs (miRNAs) regulate cancer cell behavior and may be attractive biomarkers for prognosis and prediction of response. Forty-four patients with RCC were recruited into this observational prospective study conducted in nine Spanish institutions. Peripheral blood samples were taken before initiation of therapy and 14 days later in patients receiving first-line therapy with sunitinib for advanced RCC. miRNA expression in peripheral blood was assessed using microarrays and L2 boosting was applied to filtered miRNA expression data. Several models predicting poor and prolonged response to sunitinib were constructed and evaluated by binary logistic regression. Blood samples from 38 patients and 287 miRNAs were evaluated. Twenty-eight miRNAs of the 287 were related to poor response and 23 of the 287 were related to prolonged response to sunitinib treatment. Predictive models identified populations with differences in the established end points. In the poor response group, median time to progression was 3.5 months and the overall survival was 8.5, whereas in the prolonged response group these values were 24 and 29.5 months, respectively. Ontology analyses pointed out to cancer-related pathways, such angiogenesis and apoptosis. miRNA expression signatures, measured in peripheral blood, may stratify patients with advanced RCC according to their response to first-line therapy with sunitinib, improving diagnostic accuracy. After proper validation, these signatures could be used to tailor therapy in this setting.