Classification of renal cell carcinoma based on expression of VEGF and VEGF receptors in both tumor cells and endothelial cells

Immune dysfunction revealed by digital spatial profiling of immuno-oncology markers in progressive stages of renal cell carcinoma and in brain metastases

BACKGROUND

The tumor microenvironment (TME) contributes to cancer progression and treatment response to therapy, including in renal cell carcinoma (RCC). Prior profiling studies, including single-cell transcriptomics, often involve limited sample sizes and lack spatial orientation. The TME of RCC brain metastases, a major cause of morbidity, also remains largely uncharacterized.

METHODS

We performed digital spatial profiling on the NanoString GeoMx platform using 52 validated immuno-oncology markers on RCC tissue microarrays representing progressive stages of RCC, including brain metastases. We profiled 76 primary tumors, 27 adjacent histologically normal kidney samples, and 86 metastases, including 24 brain metastases.

RESULTS

We observed lower immune checkpoint (TIM-3 and CTLA-4), cytolytic (GZMA and GZMB), and T cell activation (CD25) protein expression in metastases compared with primary tumors in two separate cohorts. We also identified changes in macrophages in metastases, with brain metastases-susceptible patients showing less M1-like, inflammatory macrophage markers (HLA-DR and CD127) in metastatic samples. A comparison of brain metastases to extracranial metastases revealed higher expression of the anti-apoptotic, BCL-2-family protein BCL-XL and lower expression of the innate immune activator STING in brain metastases. Lower TIM-3 and CD40 in the TME of brain metastases appear to be associated with longer survival, a finding that requires further validation.

CONCLUSIONS

Compared with primary tumors, RCC metastases, including brain metastases, express lower levels of numerous markers of immune activation and current or investigational therapeutic targets. Our findings may have important implications for designing future biomarker and treatment studies and may aid in development of brain metastases-specific therapies.

Location matters: LAG3 levels are lower in renal cell carcinoma metastatic sites compared to primary tumors, and expression at metastatic sites only may have prognostic importance

While great strides have been made in the treatment of advanced renal cell carcinoma (RCC) with the emergence of immune checkpoint inhibitors (ICIs) and VEGFR-targeting drugs, sizable proportions of patients still do not respond to upfront therapy and long-term responses only occur in a minority of patients. There is therefore a great need for the development of better predictors of response and an increased understanding of mechanisms of resistance to these therapies. Alternative immune checkpoints outside the PD-1/PD-L1 axis, such as LAG3, have been implicated as one mechanism of resistance to ICIs. These checkpoints thus represent attractive therapeutic targets, and indeed the LAG3 inhibitor relatlimab was recently approved for the treatment of metastatic melanoma in combination with anti-PD-1 therapy. LAG3 inhibitors are being evaluated for RCC as well. In this context, a better understanding of LAG3 expression patterns in RCC and how they relate to clinicopathologic features of disease and response to immunotherapy may give insight into mechanisms of resistance to PD-1 inhibitors and aid in the identification of subgroups of patients more likely to benefit from certain drug regimens. In this study, we assessed LAG3 protein levels in leukocytes in normal kidney adjacent to RCC, primary RCC tumors, and matched metastatic tumors, including large numbers of brain metastases. We found that LAG3 protein levels are on average lower at metastatic sites compared to matched primary tumors, and that the difference was more pronounced in patients with high-risk clinical characteristics, including those with larger primary tumor size, grade 4 tumors, IMDC poor-risk disease, and initial presentation with brain metastases. We further saw that the prognostic value of LAG3 levels varies depending on the tissue site queried (i.e., primary tumor versus metastases), and that relatively higher LAG3 levels at metastatic sites may predict a better response to immunotherapy and longer overall survival after the development of metastatic disease. These findings may have important implications for the design of future studies involving LAG3 or other immunotherapies in RCC.

Prognostic value of DCE-CT-derived blood volume and flow compared to core biopsy microvessel density in patients with metastatic renal cell carcinoma

BACKGROUND

Angiogenesis is prominent in metastatic renal cell carcinoma (mRCC). We compared two angiogenesis assessment methods: dynamic contrast-enhanced computed tomography (DCE-CT)-derived blood volume (BV) and blood flow (BF) and core biopsy microvessel density (MVD).

METHODS

As planned in DaRenCa Study-1 study, DCE-CT and core biopsy were performed from the same tumour/metastasis at baseline. MVD was assessed by CD34 immunostaining in tumour (CD34-index_T) or tumour including necrosis (CD34-index_TN). BV and BF were assessed using the DCE-CT software. Overall survival (OS) and progression-free survival (PFS) were assessed by Kaplan-Meier analysis. Spearman coefficient (rho) tested the correlation between MVD and BV, BF, or CT density (HU).

RESULTS

At baseline, 25 patients had analysable scans and tissue. BV_deconv, BV_Patlak, and BF_deconv > median were associated with favourable OS (43.2 versus 14.6 months, p = 0.002; 31.6 versus 20.2 months, p = 0.015; and 31.6 versus 24.5 months, p = 0.019). CD34-index_T and CD34-index_TN did not correlate with age (p = 0.543), sex (p = 0.225), treatment (p = 0.848), International mRCC Database Consortium category (p = 0.152), synchronous versus metachronous metastatic disease (p = 0.378), or tumour volume (p = 0.848). CD34-index_T or CD34-index_TN > median was not associated with PFS (p = 0.441 and p = 0.854, respectively) or OS (p = 0.987 and p =0.528, respectively). CD34-index_T or CD34-index_TN was not correlated with BV, BF, or HU (rho 0.20-0.26).

CONCLUSIONS

Differently from MVD, DCE-CT-derived BV and BF had prognostic impact and may better reflect angiogenesis in mRCC.

TRIAL REGISTRATION

NCT01274273.

Expression of growth factors and their receptors in the primary renal cell carcinoma: new data and review

Introduction

The aim of our study was to investigate expression levels and the prognostic value of multiple growth factors and their receptors in the primary tumor cells of renal cell carcinoma (RCC).

Material and methods

Expression of vascular endothelial growth factor (VEGF)A, fibroblast growth factor (FGF)2, vascular endothelial growth factor receptor (VEGFR)1, VEGFR2, FGFR1, FGFR2, platelet-derived growth factor receptor (PDGFR)α, and PDGFRβ was investigated in 65 primary RCC specimens by immuhistochemical staining using the appropriate antibodies. Expression levels were evaluated by the semi-quantitative method. A search for correlations of expression levels of investigated growth factors and receptors with RCC features and patients outcomes was performed.

Results

Expression of all growth factors and their receptors was detected both on the surface and in the cytoplasm of the primary tumor cells in RCC patients. The expression of all analyzed factors was interconnected. FGFR2 expression correlated with the largest number of other growth factors and receptors. A strong correlation was revealed between high expression of the studied markers, high Fuhrman grade, and advanced RCC stages. In a univariate analysis overexpression of VEGFR2 (p <0.0001) and FGFR2 (p = 0.014) had negative influence on cancer-specific survival.

Conclusions

Expression of growth factors and tyrosine kinase receptors in the primary tumor cells is strongly interconnected and associated with unfavorable features of RCC.

The Efficacy and Safety of Tyrosine Kinase Inhibitors for Von Hippel-Lindau Disease: A Retrospective Study of 32 Patients

Background: Von Hippel-Lindau (VHL) disease is an autosomal-dominant hereditary cancer syndrome. Currently, studies on tyrosine kinase inhibitor (TKI) therapy for VHL disease are scarce. In this study, we retrospectively evaluated the efficacy and safety of four TKIs in patients with VHL disease. Methods: Patients diagnosed with VHL disease who were receiving TKIs were recruited. Patients were treated with sunitinib (n = 12), sorafenib (n = 11), axitinib (n = 6), or pazopanib (n = 3). The therapeutic response was evaluated according to the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Results: From July 2009 to September 2018, 32 patients with VHL disease were eligible and included in this study. The median duration of TKI therapy was 22 months (IQR 8.5-44.75), and the median follow-up period was 31.5 months (IQR 13.5-63.5). According to the RECIST, 9 (28%) of 32 patients showed a partial response, 15 (47%) achieved stable disease, and eight exhibited continued disease progression. A partial response was observed in 11 (31%) of 36 renal cell carcinomas, 4 (27%) of 15 pancreatic lesions, and 1 (20%) of five central nervous system (CNS) hemangioblastomas. The average tumor size decreased significantly for renal cell carcinomas (P = 0.0001), renal cysts (P = 0.027), and pancreatic lesions (P = 0.003) after TKI therapy. Common side effects included hand-foot skin reactions, diarrhea, alopecia, thrombocytopenia, and fatigue. Conclusions: Partial alleviation of VHL disease-related tumors can be achieved by TKI therapies in some patients, providing an alternative treatment strategy, and the side effects of TKIs are acceptable. Larger prospective studies are warranted to further evaluate the efficacy and safety of TKIs in patients with VHL disease.

YAP Promotes VEGFA Expression and Tumor Angiogenesis Though Gli2 in Human Renal Cell Carcinoma

BACKGROUND

High vascularization is a major characteristic of renal cell carcinoma (RCC). Thus, exploration of molecules promoting the tumor vascularization in RCC is urgent. Yes-associated Protein (YAP) is an oncogene in many cancer types, and high YAP expression was correlated with worse overall survival of RCC patients according to The Cancer Genome Atlas (TCGA) database. However, whether YAP promotes tumor angiogenesis of RCC is still unknown.

METHODS

Western blotting assay, real-time Quantitive PCR analysis, and ELISA assay were used to detect the related gene expression. The function of YAP on tumor angiogenesis was investigated by HUVEC recruitment, tube formation, and rabbit cornea assay. The clinical relevance of several genes was analyzed in a public database.

RESULTS

knockdown of YAP decreased RCC cell-inducing HUVEC recruitment and tube formation. Moreover, tumor angiogenesis ability of 786-O cells was crippled by YAP knockdown in vivo. In addition, the expression of Vascular endothelial growth factors A (VEGFA) was positively correlated with YAP expression in RCC tumor tissues, and YAP promoted expression and secretion of VEGFA in RCC cells. Mechanistically, GLI family zinc finger 2 (Gli2) knockdown in RCC cells reduced both basic and YAP-induced VEGFA expression, HUVECs recruitment, and tube formation, indicating that Gli2 is necessary for YAP to promote expression of VEGFA.

CONCLUSION

Taken together, our results demonstrate that YAP/Gli2 promotes VEGFA expression and tumor angiogenesis in RCC cells, which could provide novel therapeutic targets in RCC treatment.

The role of STAT3 protein as a prognostic factor in the clear cell renal carcinoma. Systematic review

CONTEXT AND OBJECTIVE

There have been significant advances in the knowledge of renal carcinogenesis n the last years. Nowadays, renal tumors are classified according to their genetic profile and specific treatments based on the identification of therapeutic targets have also been developed. However, no prognostic markers have yet been identified. The aim of this review is to analyse literature that has evaluated the expression of the STAT3 protein as a molecular marker in clear cell renal carcinoma (ccRCC).

EVIDENCE ACQUISITION

In January 2018 a systematic review was conducted in Pubmed, Cochrane library and Sciencedirect databases, from papers published from 1990. Search terms were"renal cell carcinoma"and"STAT3"or"STAT-3"and"prognostic factor. Following the principles of the PRISMA declaration and the PICO selection strategy, original articles with series of patients diagnosed with localized or metastatic ccRCC, and where the activity of STAT3 is analysed as a prognostic marker, were selected. A total of 132 publications were identified, of which 10 were finally revised, for they met the inclusion criteria.

EVIDENCE SYNTHESIS

STAT3 activation (phosphorylation) through Ser727 is important during ccRCC development and progression. PSTAT3 expression seems to be a prognostic marker and an antiangiogenic-resistance marker in metastatic patients. There is little evidence as prognostic marker in patients with localized disease.

CONCLUSIONS

STAT3 (Ser 727) expression in the nucleus of the ccRCC cells can be a prognostic marker and an antiangiogenic-resistance marker. Current scientific evidence is limited and more studies are needed to demonstrate its usefulness.

Metastases to the nose from clear cell renal cell carcinoma: A case report

RATIONALE

Patients with nasal metastases are seldom seen among clear cell renal cell carcinoma (CCRCC). We report a rare case presenting as a solitary nasal cutaneous nodule, and summarize the therapeutic experience of tyrosine kinase inhibitors (TKIs).

PATIENT CONCERNS

A 86-year-old man with a chief complaint of continuous back pain for 3 months and discovery of a cutaneous nodule on the nose for a month visited the oncology department of our hospital. Maxillofacial computed tomography (CT) scans demonstrated a 1.5 × 0.9 cm and ovoid soft tissue density shade at dorsum of the nose. CT of abdomen revealed a 3.5 × 2.7 cm mass in right kidney and presenting an obvious heterogeneous enhancement.

DIAGNOSES

The pathological examination of nasal excision biopsy confirmed the diagnosis of nasal clear cell carcinoma. Immunohistochemical analysis indicated that the nasal metastatic tumor had a renal origin.

INTERVENTIONS

Sunitinib at a dose of 50 mg/day was administered initially, while the serious cutaneous toxicities, especially hand-foot syndrome, occurred to the patient. Subsequently, axitinib at a dose of 5 mg twice daily was accepted as second-line treatment.

OUTCOMES

The nasal mass shrinked significantly after 8-week treatment of axitinib, and the primary tumor has been stable till now.

LESSONS

Axitinib successfully controlled the nasal cutaneous metastasis with mild adverse reactions, and did not aggravate the cutaneous toxicities resulting from sunitinib. The incidence of cutaneous adverse events were low which had been reported by previous studies; however, it is difficult to say that axitinib is a more effective treatment modality for RCC with nasal metastases, which requires further studies.

The tyrosine-kinase inhibitor sunitinib targets vascular endothelial (VE)-cadherin: a marker of response to antitumoural treatment in metastatic renal cell carcinoma

Background

Vascular endothelial (VE)-cadherin is an endothelial cell-specific protein responsible for endothelium integrity. Its adhesive properties are regulated by post-translational processing, such as tyrosine phosphorylation at site Y⁶⁸⁵ in its cytoplasmic domain, and cleavage of its extracellular domain (sVE). In hormone-refractory metastatic breast cancer, we recently demonstrated that sVE levels correlate to poor survival. In the present study, we determine whether kidney cancer therapies had an effect on VE-cadherin structural modifications and their clinical interest to monitor patient outcome.

Methods

The effects of kidney cancer biotherapies were tested on an endothelial monolayer model mimicking the endothelium lining blood vessels and on a homotypic and heterotypic 3D cell model mimicking tumour growth. sVE was quantified by ELISA in renal cell carcinoma patients initiating sunitinib (48 patients) or bevacizumab (83 patients) in the first-line metastatic setting (SUVEGIL and TORAVA trials).

Results

Human VE-cadherin is a direct target for sunitinib which inhibits its VEGF-induced phosphorylation and cleavage on endothelial monolayer and endothelial cell migration in the 3D model. The tumour cell environment modulates VE-cadherin functions through MMPs and VEGF. We demonstrate the presence of soluble VE-cadherin in the sera of mRCC patients (n = 131) which level at baseline, is higher than in a healthy donor group (n = 96). Analysis of sVE level after 4 weeks of treatment showed that a decrease in sVE level discriminates the responders vs. non-responders to sunitinib, but not bevacizumab.

Conclusions

These data highlight the interest for the sVE bioassay in future follow-up of cancer patients treated with targeted therapies such as tyrosine-kinase inhibitors.

Tumor Microvessel Density as a Prognostic Marker in High-Risk Renal Cell Carcinoma Patients Treated on ECOG-ACRIN E2805

Purpose: Increased vascularity is a hallmark of renal cell carcinoma (RCC). Microvessel density (MVD) is one measurement of tumor angiogenesis; however, its utility as a biomarker of outcome is unknown. ECOG-ACRIN 2805 (E2805) enrolled 1,943 resected high-risk RCC patients randomized to adjuvant sunitinib, sorafenib, or placebo. We aimed to determine the prognostic and predictive role of MVD in RCC.Experimental Design: We obtained pretreatment primary RCC nephrectomy tissues from 822 patients on E2805 and constructed tissue microarrays. Using quantitative immunofluorescence, we measured tumor MVD as the area of CD34-expressing cells. We determined the association with disease-free survival (DFS), overall survival (OS), treatment arm, and clinicopathologic variables.Results: High MVD (above the median) was associated with prolonged OS for the entire cohort (P = 0.021) and for patients treated with placebo (P = 0.028). The association between high MVD and OS was weaker in patients treated with sunitinib or sorafenib (P = 0.060). MVD was not associated with DFS (P = 1.00). On multivariable analysis, MVD remained independently associated with improved OS (P = 0.013). High MVD correlated with Fuhrman grade 1-2 (P < 0.001), clear cell histology (P < 0.001), and absence of necrosis (P < 0.001) but not with gender, age, sarcomatoid features, lymphovascular invasion, or tumor size.Conclusions: High MVD in resected high-risk RCC patients is an independent prognostic, rather than predictive, biomarker of improved OS. Further studies should assess whether incorporating MVD into clinical models will enhance our ability to predict outcome and if low MVD can be used for selection of high-risk patients for adjuvant therapy trials. Clin Cancer Res; 24(1); 217-23. ©2017 AACR.

Impact of Sulfatase-2 on cancer progression and prognosis in patients with renal cell carcinoma

Heparan sulfate‐specific endosulfatase‐2 (SULF‐2) can modulate the signaling of heparan sulfate proteoglycan‐binding proteins. The involvement of SULF‐2 in cancer growth varies by cancer type. The roles of SULF‐2 expression in the progression and prognosis of renal cell carcinomas (RCC) have not yet been fully clarified. In the present study, the expression levels of SULF‐2 mRNA and protein in 49 clinical RCC samples were determined by RT‐PCR and immunostaining. The existence of RCC with higher SULF‐2 expression and lower SULF‐2 expression compared to the adjacent normal kidney tissues was suggested. High SULF‐2 expression was correlated with an early clinical stage and less invasive pathological factors. Low SULF‐2 expression was correlated with an advanced stage and higher invasive factors. Three‐year cancer‐specific survival (CSS) for high SULF‐2 RCC and low SULF‐2 RCC were 100% and 71.4%, respectively (log‐rank P = 0.0019), with a significantly shorter CSS observed in low SULF‐2 RCC patients. The influence of SULF‐2 expression level on Wnt/VEGF/FGF signaling, cell viability and invasive properties was examined in three RCC cell lines, Caki‐2, ACHN and 786‐O, using a SULF‐2 suppression model involving siRNA or a SULF‐2 overexpression model involving a plasmid vector. High SULF‐2 expression enhanced Wnt signaling and Wnt‐induced cell viability, but not cell invasion. In contrast, low levels of SULF‐2 expression significantly enhanced both cell invasion and viability through the activation of VEGF/FGF pathways. RCC with lower SULF‐2 expression might have a higher potential for cell invasion and proliferation, leading to a poorer prognosis via the activation of VEGF and/or FGF signaling.

Expression and prognostic significance of VEGF and mTOR pathway proteins in metastatic renal cell carcinoma patients: a prognostic immunohistochemical profile for kidney cancer patients

PURPOSE

To identify prognostic molecular profiles in patients with mRCC treated with sunitinib, we performed immunohistochemical analysis for VEGF and PI3K/Akt/mTOR pathway components.

METHODS

The immunohistochemical expression of VEGF, p85α, p110γ, PTEN, p-Akt, p-mTOR, p-4E-BP1 and p-p70S6K was studied in 79 patients with mRCC who received first-line treatment with sunitinib. Expression was correlated with clinicopathological features and survival.

RESULTS

VEGF was highly expressed (median H-Score 150), while positivity for the markers of the PI3K/Akt/mTOR pathway was: p85α 43/66 (65 %), p110γ41/60 (68 %), PTEN 32/64 (50 %), p-Akt57/63 (90 %), p-mTOR48/64 (75 %), p-4E-BP1 58/64 (90 %) and p-p70S6K 60/65 (92 %). No single immunohistochemical marker was found to have prognostic significance. Instead, the combination of increased p-mTOR and low VEGF expression was adversely correlated with overall survival (OS) (3.2 vs. 16.9 months, P = 0.001).

CONCLUSION

Immunohistochemistry for VEGF and p-mTOR proteins may discriminate patients refractory to first-line sunitinib with poor prognosis. Prospective validation of our findings is needed.

MET Inhibition in Clear Cell Renal Cell Carcinoma

Background: Clear cell renal cell carcinoma (ccRCC) is the most lethal form of kidney cancer. Small molecule VEGFR inhibitors are widely used but are not curative and various resistance mechanisms such as activation of the MET pathway have been described. Dual MET/VEGFR2 inhibitors have recently shown clinical benefit but limited preclinical data evaluates their effects in ccRCC.

Methods: An interrogation of the Cancer Genome Atlas (TCGA) dataset was performed to evaluate oncogenic alterations in the MET/VEGFR2 pathway. We evaluated the in vitro effects of Cabozantinib, a dual MET/VEGFR2 inhibitor, using a panel of ccRCC cell lines. Drug effects of cell viability and proliferation, migration, cell scatter, anchorage independent growth, and downstream MET/VEGFR2 signaling pathways were assessed.

Results: Twelve percent of TCGA cases had possible MET/HGF oncogenic alterations with co-occurrence noted (p<0.001). MET/HGF altered cases had worse overall survival (p=0.044). Cabozantinib was a potent inhibitor of MET and VEGFR2 in vitro in our cell line panel. PI3K, MAPK and mTOR pathways were also suppressed by cabozantinib, however the effects on cell viability in vitro were modest. At nanomolar concentrations of cabozantinib, HGF-stimulated migration, invasion, cellular scattering and soft agar colony formation were inhibited.

Conclusions: We provide further preclinical rationale for dual MET/VEGFR2 inhibition in ccRCC. While the MET pathway is implicated in VEGFR resistance, dual inhibitors may have direct anti-tumor effects in a patient subset with evidence of MET pathway involvement. Cabozantinib is a potent dual MET/VEGFR2 inhibitor, significantly inhibits cell migration and invasion in vitro and likely has anti-angiogenic effects similar to other VEGFR tyrosine kinase inhibitors. Future work involving in vivo models will be useful to better define mechanisms of potential anti-tumor activity.

PAX-8 expression in renal tumours and distant sites: a useful marker of primary and metastatic renal cell carcinoma?

AIMS

Immunohistochemical stains have greatly improved the diagnostic accuracy of renal cell carcinoma (RCC) for primary and distant tumours. We evaluate a marker that has recently been incorporated in clinical practice, PAX-8, in primary and metastatic RCCs.

METHODS

Two distinct tissue microarrays were used, one consisting of over 334 renal tumours, 294 with adjacent normal kidney and the other with 40 matched nephrectomy and metastatic sites of RCC. PAX-8 expression was assessed by a method of quantitative immunofluorescence.

RESULTS

PAX-8 was positive in 96% (146/152) of normal renal tissue and 83% (227/272) of renal tumours. PAX-8 staining was positive in clear cell, papillary and chromophobe tumours in 80% (165/207), 95% (39/41) and 100% (6/6) of samples, respectively. Overall, intensity of PAX-8 expression was significantly higher in RCC metastatic sites than in the primary site (p=0.0047), however, in matched sites there was no statistically significant difference in the proportion of positive versus negative specimens (p=0.274).

CONCLUSIONS

As the role of molecular markers expands in the diagnostic algorithm, this study confirms that PAX-8 expression is a useful diagnostic marker for RCC. PAX-8 expression was found in the primary tumour and distant sites. Compared with normal tissue and other histological types, clear cell RCC has lower PAX-8 expression and is less frequently positive, therefore, the lack of expression does not exclude a tumour of renal origin.

Tumor VEGF expression correlates with tumor stage and identifies prognostically different groups in patients with clear cell renal cell carcinoma

OBJECTIVES

Vascular endothelial growth factor (VEGF) is a potent inducer of tumor angiogenesis and represents the key element in the pathogenesis of clear cell renal cell carcinoma (ccRCC). The aim of this study was to investigate the use of tumor VEGF expression as a parameter to identify tumor stage and prognostically different patient groups.

METHODS AND MATERIALS

We retrospectively collected clinical data of 137 patients treated with partial or radical nephrectomy at our institutions for organ-confined, locally advanced, and metastatic ccRCCs between 1984 and 2013. Tumor cell VEGF immunohistochemical expression was compared with pathological and clinical features including age, sex, tumor stage, and Fuhrman grade. Comparison of VEGF expression levels between tumor stages was performed via Kruskal-Wallis nonparametric test. Survival analysis was conducted via Kaplan-Meier product-limit method, and Mantel-Haenszel log-rank test was employed to compare survival among groups.

RESULTS

Median age at diagnosis was 61 years (range: 33-85 y). Tumor stage was pT1N0M0 in 67 patients (49%), pT2N0M0 in 5 (4%), and pT3N0M0 in 25 (18%), while 40 patients (29%) had metastatic tumors at diagnosis. Fuhrman nuclear grade was G1 in 22 patients (16%), G2 in 60 (44%), G3 in 33 (24%), G4 in 13 patients (9%), and unknown in 9 patients. Tumor VEGF was differentially expressed among different stages (P<0.001) and in low (G1-2) and high (G3-4) Fuhrman grade tumors (P<0.001). No significant differences were found when stratifying by sex (P = 0.06) or age (P = 0.29). Median overall survival (OS) from partial or radical nephrectomy was 161 months (range: 1-366). We observed a significantly longer OS in patients with low (<25%) vs. high (>25%) VEGF expression levels (median OS 206 vs. 65 mo, P<0.001).

CONCLUSIONS

Our data show that tumor cell VEGF expression is significantly associated with tumor stage and Fuhrman grade and is able to predict patient outcome, suggesting a potential use of this parameter in identifying prognostically different patients with ccRCC.

Microvessel area as a predictor of sorafenib response in metastatic renal cell carcinoma

Background

Sorafenib was the first Food and Drug Administration approved anti-angiogenic therapy for renal cell carcinoma (RCC). Currently, there are no validated predictive biomarkers for sorafenib. Our purpose was to determine if sorafenib target expression is predictive of sorafenib sensitivity.

Methods

We used an automated, quantitative immunofluorescence-based method to determine expression levels of sorafenib targets VEGF, VEGF-R1, VEGF-R2, VEGF-R3, c-RAF, B-RAF, c-Kit, and PDGFR-β in a cohort of 96 patients treated with sorafenib. To measure vasculature in the tumor samples, we measured microvessel area (MVA) by CD-34 staining.

Results

Of the markers studied, only high MVA was predictive of response (p = 0.005). High MVA was associated with smaller primary tumors (p = 0.005). None of the biomarkers studied was predictive of overall or progression-free survival. Using the Bonferroni adjustment correcting for 9 variables with an alpha of 0.05, MVA remained significantly associated with sorafenib response.

Conclusions

Our results suggest that high MVA in tumor specimens might be associated with a greater likelihood of response to therapy. Further studies are needed to confirm these results in additional patients and in patients receiving other VEGF-R2 inhibitors, as MVA might be useful to improve patient selection for VEGF-R2 inhibitors.

Antitumoral effects of vasoactive intestinal peptide in human renal cell carcinoma xenografts in athymic nude mice

We studied antitumor effect of VIP in human renal cell carcinoma (RCC) (A498 cells xenografted in immunosuppressed mice). VIP-treated cells gave resulted in p53 upregulation and decreased nuclear β-catenin translocation and NFκB expression, MMP-2 and MMP-9 activities, VEGF levels and CD-34 expression. VIP led to a more differentiated tubular organization in tumours and less metastatic areas. Thus, VIP inhibits growth of A498-cell tumours acting on the major issues involved in RCC progression such as cell proliferation, microenvironment remodelling, tumour invasion, angiogenesis and metastatic ability. These antitumoral effects of VIP offer new therapeutical possibilities in RCC treatment.

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.

Expression of drug targets in primary and matched metastatic renal cell carcinoma tumors

BACKGROUND

Targeted therapies in renal cell carcinoma can have different effects on primary and metastatic tumors. To pave the way for predictive biomarker development, we assessed differences in expression of targets of currently approved drugs in matched primary and metastatic specimens from 34 patients.

METHODS

Four cores from each site were embedded in tissue microarray blocks. Expression of B-Raf, C-Raf, cKIT, FGF-R1, HIF-2α, mTOR, PDGF-Rβ, VEGF-R1, VEGF-R2, VEGF-R3, VEGF, VEGF-B, VEGF-C, VEGF-D, MEK1, and ERK1/2 was studied using a quantitative immunofluorescence method.

RESULTS

No significant differences were observed in global expression levels in primary and metastatic renal cell carcinoma tumors, with the exception of MEK, which had higher expression in metastatic than primary specimens. Similarly, more ki67 positive cells were seen in metastatic specimens. Correlations between marker expression in primary and metastatic specimens were variable, with the lowest correlation seen for FGF-R1 and VEGF-D. There were no significant differences in the degree of heterogeneity in primary versus metastatic tumors.

CONCLUSIONS

Expression of most of the studied markers was similar in primary and metastatic renal cell carcinoma tumors, suggesting that predictive biomarker testing for these markers can be conducted on either the primary or metastatic tumors for most markers.

c-Met is a prognostic marker and potential therapeutic target in clear cell renal cell carcinoma

BACKGROUND

Activation of the c-Met pathway occurs in a range of malignancies, including papillary renal cell carcinoma (RCC). Its activity in clear cell RCC is less clear. We investigated c-Met expression and inhibition in a large cohort of RCC tumors and cell lines.

METHODS

c-Met protein expression was determined by automated quantitative analysis (AQUA) on a tissue microarray (TMA) constructed from 330 RCC tumors paired with adjacent normal renal tissue. c-Met expression and selective inhibition with SU11274 and ARQ 197 were studied in clear cell RCC cell lines.

RESULTS

Higher c-Met expression was detected in all RCC subtypes than in the adjacent normal renal tissue (P < 0.0001). Expression was highest in papillary and sarcomatoid subtypes, and high-grade and stage tumors. Higher c-Met expression correlated with worse disease-specific survival [risk ratio = 1.36; 95% confidence interval (CI) 1.08-1.74; P = 0.0091] and was an independent predictor of survival, maintained in clear cell subset analyses. c-Met protein was activated in all cell lines, and proliferation (and colony formation) was blocked by SU11274 and ARQ 197.

CONCLUSIONS

c-Met is associated with poor pathologic features and prognosis in RCC. c-Met inhibition demonstrates in vitro activity against clear cell RCC. Further study of ARQ 197 with appropriate biomarker studies in RCC is warranted.

Vascularity of primary and metastatic renal cell carcinoma specimens

Purpose

Anti-angiogenic therapies are among the most commonly used drugs in renal cell carcinoma. Tumor vascularity, defined by microvessel area, may be associated with response to these drugs. Clinical studies suggest that metastatic sites are more responsive than primary tumors. Our purpose was to characterize microvessel area (MVA) in matched primary and metastatic samples and in samples of different histologies.

Methods

We employed a method of automated, quantitative analysis of in situ tumor components to identify the area of CD-34 staining endothelial cells within renal cell carcinoma tumors. MVA was assessed in corresponding primary and metastatic samples from 34 patients, as well as in 334 primary nephrectomy specimens with variable histologies.

Results

MVA measurements from different parts of the same tumor correlated well (R = 0.75), indicating that MVA was fairly uniform within a tumor. While MVA was slightly higher in primary tumors than corresponding metastatic sites, the difference was not statistically significant (P = 0.1). MVA in paired primary and metastatic samples correlated moderately well (R = 0.36). MVA was higher in clear cell than papillary histology and oncocytomas (P < 0.0001 and P = 0.018, respectively).

Conclusions

Lack of significant differences MVA in matched primary and metastatic samples suggests that both types of tumors should respond to anti-angiogenic drugs. This should be confirmed on additional cohorts. Given the small cohort, future predictive biomarker studies entailing MVA measurements should include specimens from both sites. Clear cell carcinomas are more vascular than other histologic subtypes, which may explain the higher response rates to anti-angiogenic therapies in clear cell tumors.

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.

Tubular network formation by adriamycin-resistant MCF-7 breast cancer cells is closely linked to MMP-9 and VEGFR-2/VEGFR-3 over-expressions

We have previously demonstrated that matrix metalloproteinase-9 (MMP-9) is critical for breast cancer cell migration and is necessary but not sufficient for tubular network formation. Given the important angiogenic activity of vascular endothelial growth factor (VEGF), we investigate here its possible contribution in tubular network formation and its link with MMP-9. Exposure of resistant epithelial breast cancer cells (rMCF-7) to Avastin, a VEGF neutralising antibody, suppresses tubular network formation but not cell migration. However, their exposure to MMP-9 inhibitor markedly decreases both parameters. Besides, the addition of exogenous VEGF or MMP-9 alone or in combination to sensitive parental cells (sMCF-7) or rMCF-7 cells enhances tubular network formation by rMCF-7 cells but not by sMCF-7 cells. The evaluation of the expression levels of VEGF receptor (VEGFR) subtypes shows that sMCF-7 cells express only small quantities of VEGFR-2 and VEGFR-3 compared with rMCF-7 cells that express strong quantities. However, treatment of sMCF-7 cells by phorbol 12-myristate 13-acetate (PMA), a PKC activator, induces both tubular network formation and VEGFR-2/VEGFR-3 over-expressions. Interestingly, exposure of rMCF-7 cells or PMA-treated sMCF-7 cells to the specific inhibitors of VEGFR-2 and VEGFR-3 reduces markedly the tubular network formation. Together, our results demonstrate that the proteolytic enzyme MMP-9 promotes rMCF-7 cell migration and, consequently, tubular network formation through VEGFR-2/ VEGFR-3 activation. Understanding of mechanisms involved in vasculogenic mimicry and cell migration related to MMP-9 and VEGF may open new opportunities to improve cancer therapy.

Pilot trial of sunitinib therapy in patients with von Hippel-Lindau disease

BACKGROUND

Von Hippel-Lindau (VHL) disease induces vascular neoplasms in multiple organs. We evaluated the safety and efficacy of sunitinib in VHL patients and examined the expression of candidate receptors in archived tissue.

METHODS

Patients with VHL were given four cycles of 50 mg sunitinib daily for 28 days, followed by 14 days off. Primary end point was toxicity. Modified RECIST were used for efficacy assessment. We evaluated 20 archival renal cell carcinomas (RCCs) and 20 hemangioblastomas (HBs) for biomarker expression levels using laser-scanning cytometry (LSC).

RESULTS

Fifteen patients were treated. Grade 3 toxicity included fatigue in five patients. Dose reductions were needed in 10 patients. Eighteen RCC and 21 HB lesions were evaluable. Six of the RCCs (33%) responded partially, versus none of the HBs (P = 0.014). LSC revealed that mean levels of phosphorylated vascular endothelial growth factor receptor-2 were lower in HB than in RCC endothelium (P = 0.003) and mean phosphorylated fibroblast growth factor receptor substrate-2 (pFRS2) levels were higher in HB (P = 0.003).

CONCLUSIONS

Sunitinib treatment in VHL patients showed acceptable toxicity. Significant response was observed in RCC but not in HB. Greater expression of pFRS2 in HB tissue than in RCC raises the hypothesis that treatment with fibroblast growth factor pathway-blocking agents may benefit patients with HB.

CD70 expression patterns in renal cell carcinoma

CD70 is up-regulated in several malignancies, where it induces cytotoxic effects on B and T lymphocytes, leading to immune escape. Novel therapeutic agents targeting CD70 have entered clinical trials. We characterized expression of CD70 protein in renal cell carcinoma specimens of various histologic subtypes and assessed their prognostic value and association with clinical/pathologic variables. We used tissue microarrays containing 330 cases using a novel fluorescent immunohistochemistry-based method of Automated Quantitative Analysis of in situ protein expression. The mean expression of CD70 was almost twice as high in tumors relative to normal tissue (P < .0001). When broken into subsets, CD70 was higher in sarcomatoid and clear cell tumors (P < .0001) and was variably elevated in oncocytomas and some papillary tumors. No association was found between CD70 expression and stage or grade. High CD70 expression was associated with decreased survival on univariate analysis in the clear cell subset of renal cell carcinoma; however, it did not retain significance on multivariate analysis. Given the elevated expression of CD70 in clear cell, sarcomatoid, and some papillary tumors, our findings suggest that CD70 might be a good drug target in renal cell carcinoma. Additional studies are warranted to assess the association between expression of CD70 and response to therapy with CD70-targeting drugs in renal cell carcinoma.

The use of automated quantitative analysis to evaluate epithelial-to-mesenchymal transition associated proteins in clear cell renal cell carcinoma

Background

Epithelial-to-mesenchymal transition (EMT) has recently been implicated in the initiation and progression of renal cell carcinoma (RCC). Some mRNA gene expression studies have suggested a link between the EMT phenotype and poorer clinical outcome from RCC. This study evaluated expression of EMT-associated proteins in RCC using in situ automated quantitative analysis immunofluorescence (AQUA) and compared expression levels with clinical outcome.

Methods/Principal Findings

Unsupervised hierarchical cluster analysis of pre-existing RCC gene expression array data (GSE16449) from 36 patients revealed the presence of an EMT transcriptional signature in RCC [E-cadherin high/SLUG low/SNAIL low]. As automated immunofluorescence technology is dependent on accurate definition of the tumour cells in which measurements take place is critical, extensive optimisation was carried out resulting in a novel pan-cadherin based tumour mask that distinguishes renal cancer cells from stromal components. 61 patients with ccRCC and clinical follow-up were subsequently assessed for expression of EMT-associated proteins (WT1, SNAIL, SLUG, E-cadherin and phospho-β-catenin) on tissue microarrays. Using Kaplan-Meier analysis both SLUG (p = 0.029) and SNAIL (p = 0.024) (log rank Mantel-Cox) were significantly associated with prolonged progression free survival (PFS). Using Cox regression univariate and multivariate analysis none of the biomarkers were significantly correlated with outcome. 14 of the 61 patients expressed the gene expression analysis predicted EMT-protein signature [E-cadherin high/SLUG low/SNAIL low], which was not found to be associated to PFS when measured at the protein level. A combination of high expression of SNAIL and low stage was able to stratify patients with greater significance (p = 0.001) then either variable alone (high SNAIL p = 0.024, low stage p = 0.029).

Conclusions

AQUA has been shown to have the potential to identify EMT related protein targets in RCC allowing for stratification of patients into high and low risk groups, as well the ability to assess the association of reputed EMT signatures to progression of the disease.

Characterization and targeting of phosphatidylinositol-3 kinase (PI3K) and mammalian target of rapamycin (mTOR) in renal cell cancer

Background

PI3K and mTOR are key components of signal transduction pathways critical for cell survival. Numerous PI3K inhibitors have entered clinical trials, while mTOR is the target of approved drugs for metastatic renal cell carcinoma (RCC). We characterized expression of p85 and p110α PI3K subunits and mTOR in RCC specimens and assessed pharmacologic co-targeting of these molecules in vitro.

Methods

We employed tissue microarrays containing 330 nephrectomy cases using a novel immunofluorescence-based method of Automated Quantitative Analysis (AQUA) of in situ protein expression. In RCC cell lines we assessed synergism between PI3K and mTOR inhibitors and activity of NVP-BEZ235, which co-targets PI3K and mTOR.

Results

p85 expression was associated with high stage and grade (P < 0.0001 for both). High p85 and high mTOR expression were strongly associated with decreased survival, and high p85 was independently prognostic on multi-variable analysis. Strong co-expression of both PI3K subunits and mTOR was found in the human specimens. The PI3K inhibitor LY294002 and rapamycin were highly synergistic in all six RCC cell lines studied. Similar synergism was seen with all rapamycin concentrations used. NVP-BEZ235 inhibited RCC cell growth in vitro with IC₅₀s in the low ηM range and resultant PARP cleavage.

Conclusions

High PI3K and mTOR expression in RCC defines populations with decreased survival, suggesting that they are good drug targets in RCC. These targets tend to be co-expressed, and co-targeting these molecules is synergistic. NVP-BEZ235 is active in RCC cells in vitro; suggesting that concurrent PI3K and mTOR targeting in RCC warrants further investigation.

Molecular diagnostics in urologic malignancies: a work in progress

CONTEXT

Molecular diagnostic applications are now an integral part of the management algorithms of several solid tumors, such as breast, colon, and lung. In stark contrast, the current clinical management of urologic malignancies is lagging behind. Clinically robust molecular tests that can identify patients who are more likely to respond to a given targeted agent or even those in need of a more aggressive treatment based on well-validated molecular prognosticators are still lacking. Several promising biomarkers for detection, prognosis, and targeted therapeutics are being evaluated.

OBJECTIVE

To discuss candidate biomarkers that may soon make the transition to clinical assay for patients in urologic oncology.

DATA SOURCES

Selected original articles published in the PubMed service of the US National Library of Medicine.

CONCLUSIONS

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 in these prevalent, frequently lethal solid tumors.

Signaling pathways in renal cell carcinoma

Renal cell carcinoma (RCC), the most lethal type of genitourinary cancer, is generally resistant to chemotherapy and radiation therapy. Surgical excision of the tumor at a localized stage remains the mainstay for curative therapy. A number of drugs developed in recent years have shown limited to significant efficacy in treating RCC. These drugs act by blocking critical signaling pathways associated with RCC tumor growth and survival, and angiogenesis. Beyond well-validated signaling targets such as VHL, VEGFR and mTOR, additional pathways including HGF/c-MET and Wnt/β-catenin have emerged as important to RCC pathogenesis. Mutations in one or more components of these signaling networks may affect tumor response to therapy. This review summarizes the state of knowledge about signaling pathways in RCC and discusses the known genetic and epigenetic alterations that underlie dysregulation of these pathways.

Theranostic and prognostic biomarkers: genomic applications in urological malignancies

Compared to other solid tumours such as breast, colon, and lung, the current clinical management of urological malignancies is lagging behind in terms of utilisation of clinically robust molecular tests that can identify patients that are more likely to respond to a given targeted agent, or even those in need of a more aggressive treatment approach based on well-validated molecular prognosticators. Several promising biomarkers for detection, prognosis, and targeted therapeutics are now under evaluation. The following review discusses some of the candidate biomarkers that may soon make their transition into clinically applicable assays in urological oncology patients.

In situ identification of putative cancer stem cells by multiplexing ALDH1, CD44, and cytokeratin identifies breast cancer patients with poor prognosis

A subset of cells, tentatively called cancer stem cells (CSCs), in breast cancer have been associated with tumor initiation, drug resistance, and tumor persistence or aggressiveness. They are characterized by CD44 positivity, CD24 negativity, and/or ALDH1 positivity in flow cytometric studies. We hypothesized that the frequency or density of these cells may be associated with more aggressive tumor behavior. We borrowed these multiplexed, flow-based methods to develop an in situ method to define CSCs in formalin-fixed paraffin-embedded breast cancer tissue, with the goal of assessing the prognostic value of the presence of CSCs in breast cancer. Using a retrospective collection of 321 node-negative and 318 node-positive patients with a mean follow-up time of 12.6 years, we assessed TMAs using the AQUA method for quantitative immunofluorescence. Using a multiplexed assay for ALDH1, CD44, and cytokeratin to measure the coexpression of these proteins, putative CSCs appear in variable sized clusters and in 27 cases (of 490), which showed significantly worse outcome (log rank P = 0.0003). Multivariate analysis showed that this marker combination is independent of tumor size, histological grade, nodal status, ER-, PR,- and HER2-status. In this cohort, ALDH1 expression alone does not significantly predict outcome. We conclude that the multiplexed method of in situ identification of putative CSCs identifies high risk patients in breast cancer.

Automated analysis of tissue microarrays

The analysis of protein expression in tissue by immunohistochemistry (IHC) presents three significant challenges. They are (1) the time-consuming nature of pathologist-based scoring of slides; (2) the need for objective quantification and localization of protein expression; and (3) the need for a highly reproducible measurement to limit intra- and inter-observer variability. While there are a variety of commercially available platforms for automated chromagen-based and fluorescence-based image acquisition of tissue microarrays, this chapter is focused on the analysis of fluorescent images by AQUA(R) analysis (Automated QUantitative Analysis) and the solutions offered by such a method for research and diagnostics. AQUA analysis is a method for molecularly defining regions of interest or "compartments" within a tissue section. The methodology can be utilized with tissue microarrays to provide rapid, quantitative, localized, and reproducible protein expression data that can then be used to identify statistically relevant correlations in populations. Ultimately this allows for a multiplexed, objective and standardized quantitative approach for biomarker research and diagnostic assay development for protein expression in tissue.