Clinical effect and future considerations for molecularly-targeted therapy in renal cell carcinoma

Case report: Adjuvant therapy with toceranib for an incompletely resected renal cell carcinoma with suspected pulmonary metastasis in a dog

Primary renal neoplasia is rare in humans and dogs, with renal cell carcinoma (RCC) being the most common form of this cancer. As RCC is often diagnosed at an advanced stage, pulmonary metastasis is frequently observed. Tyrosine kinase inhibitors (TKIs) are the standard adjuvant treatments for metastatic RCC in humans. Similarly, in veterinary medicine, recent trials have employed TKIs for early-stage RCC patients who underwent complete surgical resection and showed no distant metastasis. However, the use of TKIs has not yet been reported commonly in cases of advanced RCC with metastasis. This case study presents the first clinical outcomes of TKI therapy in a dog with incompletely resected RCC and metastasis. A 5-year-old spayed female Chihuahua was referred to our hospital with a right renal mass and multiple pulmonary nodules suspected to be metastases. A portion of the renal mass was surgically removed, and histopathological examination revealed RCC with a high mitotic index. Adjuvant chemotherapy was administered, owing to incomplete resection with suspected pulmonary metastasis. An anticancer drug response prediction test was conducted using patient tissues. Since toceranib showed the most favorable responsiveness, it was selected as a therapeutic agent. Toceranib was orally administered at a dosage of 2.27 mg/kg every 48 h. Regular medical records for potential adverse effects were obtained, including systemic blood pressure, complete blood count, serum biochemical examination, and urinalysis. After 2 weeks of toceranib therapy, partial remission of pulmonary nodules continued for 2 months. The patient did not experience any adverse effects of the anticancer drug during the 4-month follow-up period. However, the patient died from an unidentified cause 6 months after the initial detection of the renal mass. This report describes the use of toceranib in dogs with RCC. In the present case, the patient showed an initial response to chemotherapy, and despite the presence of several poor prognostic factors, the dog survived beyond the expected 3-month lifespan to 6 months. Notably, no adverse events were observed during treatment.

Renal cell carcinoma therapy: Current and new drug candidates

Renal cell carcinoma (RCC) is the most common and lethal tumor of the urological system. Curative treatment of localized RCC includes nephrectomy, radio-ablation, and active surveillance, whereas metastatic RCC (mRCC) requires a combination of surgery and systemic therapy. Response to conventional therapy is limited but, recently, many novel therapies for mRCC have emerged, including targeted therapies and new immunotherapeutic agents. Nevertheless, development of resistance and limited durable responses demand new anticancer candidates with improved selectivity and efficacy. In this review, we summarize recent preclinical studies of novel natural and synthetic compounds to treat RCC, detailing their mechanisms of action and anticancer activities.

Renal Cell Tumors: Uncovering the Biomarker Potential of ncRNAs

Renal cell tumors (RCT) remain as one of the most common and lethal urological tumors worldwide. Discrimination between (1) benign and malignant disease, (2) indolent and aggressive tumors, and (3) patient responsiveness to a specific therapy is of major clinical importance, allowing for a more efficient patient management. Nonetheless, currently available tools provide limited information and novel strategies are needed. Over the years, a putative role of non-coding RNAs (ncRNAs) as disease biomarkers has gained relevance and is now one of the most prolific fields in biological sciences. Herein, we extensively sought the most significant reports on ncRNAs as potential RCTs' diagnostic, prognostic, predictive, and monitoring biomarkers. We could conclude that ncRNAs, either alone or in combination with currently used clinical and pathological parameters, might represent key elements to improve patient management, potentiating the implementation of precision medicine. Nevertheless, most ncRNA biomarkers require large-scale validation studies, prior to clinical implementation.

Clinicopathological implications of the expression of vascular endothelial growth factor and programmed death ligand 1 in clear-cell renal cell carcinoma

Combined anti-VEGF/anti-programmed death ligand 1 (PD-L1) therapy synergistically improves treatment outcomes in advanced renal cell carcinoma (RCC) compared with anti-PD-L1 or anti-vascular endothelial growth factor (VEGF) monotherapy. Here, we analyzed the expression of VEGF and PD-L1 (SP142) in a retrospective cohort of 513 patients with clear-cell (cc) RCC. PD-L1 expression on tumor cells (TCs) and immune cells (ICs) was evaluated by immunohistochemistry (IHC) with a positive threshold value of ≥1%. Positive staining for PD-L1 on ICs and TCs was found in 115 (22.4%) and 7 (1.4%) cases, respectively. Moderate or strong staining for VEGF on TCs was found in 217 (42.3%) patients. PD-L1 expression on ICs and TCs was positively associated with VEGF expression on TCs. Both VEGF and PD-L1 (IC) positivity (VEGF/PD-L1 [IC]: +/+) was observed in 65 (12.7%) cases. Patients in this subgroup exhibited more aggressive clinicopathologic features, including older age, higher World Health Organization/International Society of Urological Pathology (ISUP) grade, angiolymphatic invasion, tumor necrosis, and sarcomatoid differentiation (P < 0.05). Kaplan-Meier analysis indicated that expression of VEGF and PD-L1 on ICs was positively correlated with tumor recurrence (P < 0.001), whereas expression of PD-L1 on TCs was not (P = 0.554). Tumors with positivity for both antibodies (VEGF/PD-L1 [IC]: +/+) exhibited the worst recurrence-free survival (P < 0.001), and double positivity independently predicted tumor recurrence in ccRCC. The present study provides comprehensive and basic information about VEGF and PD-L1 expression for new combined therapy in primary ccRCC.

Characterisation of the Morphological, Functional and Molecular Changes in Sunitinib-Resistant Renal Cell Carcinoma Cells

Sunitinib resistance is a major clinical problem hampering the treatment of renal cell carcinoma (RCC). Studies on the comprehensive characterisation of morphological, functional and molecular changes in sunitinib-resistant RCC cells are lacking. The aim of the current study was to develop sunitinib resistance in four human RCC cell lines (786-0, Caki-1, Caki-2 and SN12K1), and to characterise the changed cell biology with sunitinib resistance. RCC cells were made resistant by continuous, chronic exposure to 10 μM of sunitinib over a period of 12 months. Cell proliferation, morphology, transmigration, and gene expression for interleukin-6 (IL-6), interleukin-8 (IL-8), vascular endothelial growth factor (VEGF), Bcl-2 and Bax were studied. There was no significant difference in growth rate or transmigration between the parental and resistant cells. Sunitinib-resistant cells were significantly hypertrophic compared with parental cells as evidenced by increases in the surface areas of the whole cells and the nuclei. IL-6 was significantly increased in all resistant cells. IL-8 was increased in sunitinib-resistant Caki-2 and SN12K1 cells and decreased in 786-0 without any significant changes in Caki-1. VEGF was increased in resistant Caki-2 and SN12K1 cells but not in 786-0 and Caki-1. The Bcl2/Bax ratio was increased in Caki-1, Caki-2 and SN12K1 cells but decreased in 786-0 cells. The increased IL-6 may contribute to sunitinib resistance either via VEGF-mediated angiogenesis or through shifting of the Bcl2/Bax balance in favour of anti-apoptosis.

Ultrasound Measurement of Vascular Density to Evaluate Response to Anti-Angiogenic Therapy in Renal Cell Carcinoma

BACKGROUND

Functional and molecular changes often precede gross anatomical changes, so early assessment of a tumor's functional and molecular response to therapy can help reduce a patient's exposure to the side effects of ineffective chemotherapeutics or other treatment strategies.

OBJECTIVE

Our intent was to test the hypothesis that an ultrasound microvascular imaging approach might provide indications of response to therapy prior to assessment of tumor size.

METHODS

Mice bearing clear-cell renal cell carcinoma xenograft tumors were treated with antiangiogenic and Notch inhibition therapies. An ultrasound measurement of microvascular density was used to serially track the tumor response to therapy.

RESULTS

Data indicated that ultrasound-derived microvascular density can indicate response to therapy a week prior to changes in tumor volume and is strongly correlated with physiological characteristics of the tumors as measured by histology ([Formula: see text]). Furthermore, data demonstrated that ultrasound measurements of vascular density can determine response to therapy and classify between-treatment groups with high sensitivity and specificity.

CONCLUSION/SIGNIFICANCE

Results suggests that future applications utilizing ultrasound imaging to monitor tumor response to therapy may be able to provide earlier insight into tumor behavior from metrics of microvascular density rather than anatomical tumor size measurements.

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.

Ultrasound Molecular Imaging of VEGFR-2 in Clear-Cell Renal Cell Carcinoma Tracks Disease Response to Antiangiogenic and Notch-Inhibition Therapy

Metastatic clear-cell renal cell carcinoma (ccRCC) affects thousands of patients worldwide each year. Antiangiogenic therapy has been shown to have beneficial effects initially, but resistance is eventually developed. Therefore, it is important to accurately track the response of cancer to different therapeutics in order to appropriately adjust the therapy to maximize efficacy. Change in tumor volume is the current gold standard for determining efficacy of treatment. However, functional variations can occur much earlier than measurable volume changes. Contrast-enhanced ultrasound (CEUS) is an important tool for assessing tumor progression and response to therapy, since it can monitor functional changes in the physiology. In this study, we demonstrate how ultrasound molecular imaging (USMI) can accurately track the evolution of the disease and molecular response to treatment. Methods A cohort of NSG (NOD/scid/gamma) mice was injected with ccRCC cells and treated with either the VEGF inhibitor SU (Sunitinib malate, Selleckchem, TX, USA) or the Notch pathway inhibitor GSI (Gamma secretase inhibitor, PF-03084014, Pfizer, New York, NY, USA), or started on SU and later switched to GSI (Switch group). The therapies used in the study focus on disrupting angiogenesis and proper vessel development. SU inhibits signaling of vascular endothelial growth factor (VEGF), which is responsible for the sprouting of new vasculature, and GSI inhibits the Notch pathway, which is a key factor in the correct maturation of newly formed vasculature. Microbubble contrast agents targeted to VEGFR-2 (VEGF Receptor) were delivered as a bolus, and the bound agents were imaged in 3D after the free-flowing contrast was cleared from the body. Additionally, the tumors were harvested at the end of the study and stained for CD31. Results The results show that MI can detect changes in VEGFR-2 expression in the group treated with SU within a week of the start of treatment, while differences in volume only become apparent after the mice have been treated for three weeks. Furthermore, USMI can detect response to therapy in 92% of cases after 1 week of treatment, while the detection rate is only 40% for volume measurements. The amount of targeting for the GSI and Control groups was high throughout the duration of the study, while that of the SU and Switch groups remained low. However, the amount of targeting in the Switch group increased to levels similar to those of the Control group after the treatment was switched to GSI. CD31 staining indicates significantly lower levels of patent vasculature for the SU group compared to the Control and GSI groups. Therefore, the results parallel the expected physiological changes in the tumor, since GSI promotes angiogenesis through the VEGF pathway, while SU inhibits it. Conclusion This study demonstrates that MI can track disease progression and assess functional changes in tumors before changes in volume are apparent, and thus, CEUS can be a valuable tool for assessing response to therapy in disease. Future work is required to determine whether levels of VEGFR-2 targeting correlate with eventual survival outcomes.

Elucidating mechanisms of sunitinib resistance in renal cancer: an integrated pathological-molecular analysis

Upon sunitinib treatment of metastatic renal cell carcinoma patients eventually acquire resistance. Our aim was to investigate microRNAs behind sunitinib resistance.

We developed an in vivo xenograft and an in vitro model and compared morphological, immunhistochemical, transcriptomical and miRNome data changes during sunitinib response and resistance by performing next-generation mRNA and miRNA sequencing. Complex bioinformatics (pathway, BioFunction and network) analysis were performed. Results were validated by in vitro functional assays.

Our morphological, immunhistochemical, transcriptomical and miRNome data all pointed out that during sunitinib resistance tumor cells changed to migratory phenotype. We identified the downregulated miR-1 and miR-663a targeting FRAS1 (Fraser Extracellular Matrix Complex Subunit 1) and MDGA1 (MAM Domain Containing Glycosylphosphatidylinositol Anchor 1) in resistant tumors. We proved firstly miR-1-FRAS1 and miR-663a-MDGA1 interactions. We found that MDGA1 knockdown decreased renal cancer cell migration and proliferation similarly to restoration of levels of miR-1 and miR-663.

Our results support the central role of cell migration as an adaptive mechanism to secure tumor survival behind sunitinib resistance. MDGA1, FRAS1 or the targeting miRNAs can be potential adjuvant therapeutic targets, through inhibition of cancer cell migration, thus eliminating the development of resistance and metastasis.

MicroRNAs and altered metabolism of clear cell renal cell carcinoma: Potential role as aerobic glycolysis biomarkers

BACKGROUND

Warburg Effect is a metabolic switch that occurs in most of cancer cells but its advantages are not fully understood. This switch is known to happen in renal cell carcinoma (RCC), which is the most common solid cancer of the adult kidney. RCC carcinogenesis is related to pVHL loss and Hypoxia Inducible Factor (HIF) activation, ultimately leading to the activation of several genes related to glycolysis. MicroRNAs (miRNAs) regulate gene expression at a post-transcriptional level and are also deregulated in several cancers, including RCC.

SCOPE OF REVIEW

This review focuses in the miRNAs that direct target enzymes involved in glycolysis and that are deregulated in several cancers. It also reviews the possible application of miRNAs in the improvement of clinical patients' management.

MAJOR CONCLUSIONS

Several miRNAs that direct target enzymes involved in glycolysis are downregulated in cancer, strongly influencing the Warburg Effect. Due to this strong influence, FDG-PET can possibly benefit from measurement of these miRNAs. Restoring their levels can also bring an improvement to the current therapies.

GENERAL SIGNIFICANCE

Despite being known for almost a hundred years, the Warburg Effect is not fully understood. MiRNAs are now known to be intrinsically connected with this effect and present an opportunity to understand it. They also open a new door to improve current diagnosis and prognosis tests as well as to complement current therapies. This is urgent for cancers like RCC, mostly due to the lack of an efficient screening test for early relapse detection and follow-up and the development of resistance to current therapies.

MUC13 overexpression in renal cell carcinoma plays a central role in tumor progression and drug resistance

Metastatic renal cell carcinoma is a largely incurable disease, and existing treatments targeting angiogenesis and tyrosine kinase receptors are only partially effective. Here we reveal that MUC13, a cell surface mucin glycoprotein, is aberrantly expressed by most renal cell carcinomas, with increasing expression positively correlating with tumor grade. Importantly, we demonstrated that high MUC13 expression was a statistically significant independent predictor of poor survival in two independent cohorts, particularly in stage 1 cancers. In cultured renal cell carcinoma cells MUC13 promoted proliferation and induced the cell cycle regulator, cyclin D1, and inhibited apoptosis by inducing the anti-apoptotic proteins, BCL-xL and survivin. Silencing of MUC13 expression inhibited migration and invasion, and sensitized renal cancer cells to killing by the multi-kinase inhibitors used clinically, sorafenib and sunitinib, and reversed acquired resistance to these drugs. Furthermore, we demonstrated that MUC13 promotion of renal cancer cell growth and survival is mediated by activation of nuclear factor κB, a transcription factor known to regulate the expression of genes that play key roles in the development and progression of cancer. These results show that MUC13 has potential as a prognostic marker for aggressive early stage renal cell cancer and is a plausible target to sensitize these tumors to therapy.

CCL2 as a potential therapeutic target for clear cell renal cell carcinoma

We previously reported that the pVHL‐atypical PKC‐JunB pathway contributed to promotion of cell invasiveness and angiogenesis in clear cell renal cell carcinoma (ccRCC), and we detected chemokine (C‐C motif) ligand‐2 (CCL2) as one of downstream effectors of JunB. CCL2 plays a critical role in tumorigenesis in other types of cancer, but its role in ccRCC remains unclear. In this study, we investigated the roles and therapeutic potential of CCL2 in ccRCC. Immunohistochemical analysis of CCL2 expression for ccRCC specimens showed that upregulation of CCL2 expression correlated with clinical stage, overall survival, and macrophage infiltration. For functional analysis of CCL2 in ccRCC cells, we generated subclones of WT8 cells that overexpressed CCL2 and subclones 786‐O cells in which CCL2 expression was knocked down. Although CCL2 expression did not affect cell proliferation in vitro, CCL2 overexpression enhanced and CCL2 knockdown suppressed tumor growth, angiogenesis, and macrophage infiltration in vivo. We then depleted macrophages from tumor xenografts by administration of clodronate liposomes to confirm the role of macrophages in ccRCC. Depletion of macrophages suppressed tumor growth and angiogenesis. To examine the effect of inhibiting CCL2 activity in ccRCC, we administered CCL2 neutralizing antibody to primary RCC xenografts established from patient surgical specimens. Inhibition of CCL2 activity resulted in significant suppression of tumor growth, angiogenesis, and macrophage infiltration. These results suggest that CCL2 is involved in angiogenesis and macrophage infiltration in ccRCC, and that CCL2 could be a potential therapeutic target for ccRCC.

The Wide Experience of the Sequential Therapy for Patients with Metastatic Renal Cell Carcinoma

Sequential targeted therapies are the standard of care for patients with metastatic renal cell carcinoma (mRCC). Several drugs are available for patients whose disease progresses while they receive initial tyrosine kinase inhibitor (TKI) therapy; these include nivolumab (an inhibitor of PD-1 receptor), everolimus (an inhibitor of the mechanistic target of rapamycin) or additional TKIs. Until now, there has been no clinical evidence to support the use of one strategy versus another, so investigators and physicians rely on experience, judgement and findings from molecular analyses to select the appropriate treatment. However, with the arrival of nivolumab and cabozantinib that provide an overall survival higher than other alternative treatments, therapeutic strategies may have changed. Here, we discuss findings from preclinical and clinical studies that might help clinicians to choose the optimal treatment approach for patients with mRCC who progress to initial therapy.

CRISPR-Mediated VHL Knockout Generates an Improved Model for Metastatic Renal Cell Carcinoma

Metastatic renal cell carcinoma (mRCC) is nearly incurable and accounts for most of the mortality associated with RCC. Von Hippel Lindau (VHL) is a tumour suppressor that is lost in the majority of clear cell RCC (ccRCC) cases. Its role in regulating hypoxia-inducible factors-1α (HIF-1α) and -2α (HIF-2α) is well-studied. Recent work has demonstrated that VHL knock down induces an epithelial-mesenchymal transition (EMT) phenotype. In this study we showed that a CRISPR/Cas9-mediated knock out of VHL in the RENCA model leads to morphologic and molecular changes indicative of EMT, which in turn drives increased metastasis to the lungs. RENCA cells deficient in HIF-1α failed to undergo EMT changes upon VHL knockout. RNA-seq revealed several HIF-1α-regulated genes that are upregulated in our VHL knockout cells and whose overexpression signifies an aggressive form of ccRCC in the cancer genome atlas (TCGA) database. Independent validation in a new clinical dataset confirms the upregulation of these genes in ccRCC samples compared to adjacent normal tissue. Our findings indicate that loss of VHL could be driving tumour cell dissemination through stabilization of HIF-1α in RCC. A better understanding of the mechanisms involved in this phenomenon can guide the search for more effective treatments to combat mRCC.

Contemporary Treatment of Metastatic Renal Cell Carcinoma

The introduction of targeted therapy has revolutionized the treatment of patients with metastatic renal cell carcinoma (mRCC). The current standard of care focuses on the inhibition of angiogenesis through the targeting of the vascular endothelial growth factor receptor (VEGFR) and the mammalian target of rapamycin (mTOR). Over the past few years, research exploring novel targeted agents has blossomed, leading to the approval of various targeted therapies. Furthermore, results from the CheckMate025 and the METEOR trials have brought about two additional novel options: the programmed cell death 1 (PD-1) checkpoint inhibitor nivolumab and the MET/VEGFR/AXL inhibitor cabozantinib, respectively. With the variety of therapeutic agents available for treatment of mRCC, research examining appropriate sequencing and combinations of the drugs is ongoing. This review discusses the role of prognostic criteria, such as those from the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) criteria. It also covers the current standard of treatment for mRCC with targeted therapy in first-, second-, and third-line setting. Additionally, the novel mechanism of action of nivolumab and cabozantinib, therapeutic sequencing and ongoing clinical trials are discussed.

Role of IL13RA2 in Sunitinib Resistance in Clear Cell Renal Cell Carcinoma

Vascular endothelial growth factor (VEGF) and mammalian target of rapamycin are well-known therapeutic targets for renal cell carcinoma (RCC). Sunitinib is an agent that targets VEGF receptors and is considered to be a standard treatment for metastatic or unresectable clear cell RCC (ccRCC). However, ccRCC eventually develops resistance to sunitinib in most cases, and the mechanisms underlying this resistance are not fully elucidated. In the present study, we established unique primary xenograft models, KURC1 (Kyoto University Renal Cancer 1) and KURC2, from freshly isolated ccRCC specimens. The KURC1 xenograft initially responded to sunitinib treatment, however finally acquired resistance. KURC2 retained sensitivity to sunitinib for over 6 months. Comparing gene expression profiles between the two xenograft models with different sensitivity to sunitinib, we identified interleukin 13 receptor alpha 2 (IL13RA2) as a candidate molecule associated with the acquired sunitinib-resistance in ccRCC. And patients with high IL13RA2 expression in immunohistochemistry in primary ccRCC tumor tends to have sunitinib-resistant metastatic site. Next, we showed that sunitinib-sensitive 786-O cells acquired resistance in vivo when IL13RA2 was overexpressed. Conversely, shRNA-mediated knockdown of IL13RA2 successfully overcame the sunitinib-resistance in Caki-1 cells. Histopathological analyses revealed that IL13RA2 repressed sunitinib-induced apoptosis without increasing tumor vasculature in vivo. To our knowledge, this is a novel mechanism of developing resistance to sunitinib in a certain population of ccRCC, and these results indicate that IL13RA2 could be one of potential target to overcome sunitinib resistance.

A PKM2 signature in the failing heart

A salient feature of the failing heart is metabolic remodeling towards predominant glucose metabolism and activation of the fetal gene program. Sunitinib is a multitargeted receptor tyrosine kinase inhibitor used for the treatment of highly vascularized tumors. In diabetic patients, sunitinib significantly decreases blood glucose. However, a considerable proportion of sunitinib-treated patients develop cardiac dysfunction or failure. We asked whether sunitinib treatment results in shift towards glycolysis in the heart. Glucose uptake by the heart was increased fivefold in mice treated with sunitinib. Transcript analysis by qPCR revealed an induction of genes associated with glycolysis and reactivation of the fetal gene program. Additionally, we observed a shift in the enzyme pyruvate kinase from the adult M1 (PKM1) isoform to the fetal M2 (PKM2) isoform, a hallmark of the Warburg Effect. This novel observation led us to examine whether a similar shift occurs in human heart failure. Examination of tissue from patients with heart failure similarly displayed an induction of PKM2. Moreover, this phenomenon was partially reversed following mechanical unloading. We propose that pyruvate kinase isoform switching represents a novel feature of the fetal gene program in the failing heart.

Management of metastatic renal cell carcinoma progressed after sunitinib or another antiangiogenic treatment

Prognosis of metastatic renal cell carcinoma (mRCC) has markedly improved in the recent years. Several factors such as precocious diagnosis, better supportive care, and an increased number of targeted therapies are responsible for this progress. From 2006 to date, 7 drugs have been approved for treatment of mRCC, and among these only 2 are recommended for the second line of therapy with grade 1 evidence. Tyrosine kinase inhibitors (TKIs) and mammalian target of rapamycin (mTOR) inhibitors are the strategies with more evidence, but no comparative studies are available and what is the best second line remains an open issue. Herein, we review the available evidence on the second-line treatment focusing mainly on prospective studies. We identify a special population of patients in whom more evidence is available, and we propose a possible strategy for the management of progressed mRCC and for primary resistant lesions as well as for patients who need a rapid response in lesions. In the majority of patients, several factors should be considered: toxicity reported during first-line therapy, performance status, the absence of correlation between the length of first-line therapy and the probability to respond to second-line therapy, and the lack of comparative trials between mTOR inhibitors and TKI. When an mTOR inhibitor is selected, everolimus must be preferred, although in the RECORD1 trial only the increase in progression-free survival has been reported and the increase in terms of overall survival has not been reached. When another TKI is the choice, there are no strong pieces of evidence that favor the use of a defined molecule. In every case, we recommend to start the selected targeted agents at standard dosage and to pursue therapy as long as possible because the control of disease should be the primary endpoint for the management of mRCC.

Circulating biomarkers in renal cell carcinoma: the link between microRNAs and extracellular vesicles, where are we now?

Renal cell carcinoma (RCC) is a lethal urological cancer, with incidence and mortality rates increasing by 2-3% per decade. The lack of standard screening tests contributes to the fact that one-third of patients are diagnosed with locally invasive or metastatic disease. Moreover, 20-40% of RCC patients submitted to surgical nephrectomy will develop metastasis. MicroRNAs (miRNAs) are small non-coding RNAs responsible for gene regulation at a post-transcriptional level. It is accepted that they are deregulated in cancer and can influence tumor development. Thus, miRNAs are promising RCC biomarkers, since they can be detected using non-invasive methods. They are highly stable and easier to quantify in circulating biofluids. The elevated miRNA stability in circulating samples may be the consequence of their capacity to circulate inside of extracellular microvesicles (EMVs), for example, the exosomes. The EMVs are bilayered membrane vesicles secreted by all cell types. They can be released in the interstitial space or into circulating biofluids, which allows the travelling, binding and entrance of these vesicles in receptor cells. This type of cell communication can shuttle bioactive molecules between cells, allowing the horizontal transference of genetic material. In this review, we focus on circulating miRNAs (miR-210, miR-1233, miR-221, miR-15a, miR-451, miR-508, miR-378) in the biofluids of RCC patients and attempt to establish the diagnostic and prognostic accuracy, their synergic effects, and the pathways involved in RCC biology.

Renal cell carcinoma development and miRNAs: a possible link to the EGFR pathway

Renal cell carcinoma (RCC) is the most common solid cancer of the adult kidney and the majority of RCC cases are detected accidentally. This reality and the nonexistence of a standard screening test contribute to the fact that one third of patients are diagnosed with local invasive disease or metastatic disease. miRNAs are a family of small ncRNAs that regulate gene expression and have been identified as key regulators in many biological processes including cell development, differentiation, apoptosis and proliferation. The EGF receptor signaling pathway is usually deregulated in cancer and it is suggested to have an important role in RCC. Further studies are needed to characterize deregulation of this pathway during RCC development. In this review we highlight some potential miRNAs that could be involved in the modulation of the EGF receptor pathway and consequently in RCC development.

Sunitinib resistance in renal cell carcinoma

Of the many targeted therapies introduced since 2006, sunitinib has carved its way to become the most commonly used first-line therapy for the treatment of metastatic renal cell carcinoma (RCC). Despite significant improvements in progression-free survival, 30% of the patients are intrinsically resistant to sunitinib and the remaining 70% who respond initially will eventually become resistant in 6-15 months. While the molecular mechanisms of acquired resistance to sunitinib have been unravelling at a rapid rate, the mechanisms of intrinsic resistance remain elusive. Combination therapy, sunitinib rechallenge and sequential therapy have been investigated as means to overcome resistance to sunitinib. Of these, sequential therapy appears to be the most promising strategy. This mini review summarises our emerging understanding of the molecular mechanisms, and the strategies employed to overcome sunitinib resistance.

Systematic lymph node dissection in lung metastasectomy of renal cell carcinoma: an 18 years of experience

BACKGROUND

Pulmonary metastasectomy of renal cell carcinomas (RCC) remains controversial. Thoracic lymph node involvement (LNI) is a known prognostic factor. The aim of our analysis is to evaluate whether patients with LNI, and particularly N2 patients, should be excluded from surgical treatment.

METHODS

We retrospectively reviewed data from 122 patients who underwent operations at two French thoracic surgery departments between 1993 and 2011 for RCC lung metastases.

RESULTS

The population consisted of 38 women and 84 men; the average age at time of metastasectomy was 63.3 years (min: 43, max: 82). LNI was identified as a prognostic factor using univariate and multivariate analysis (median survival: 107 months vs. 37 months, P = 0.003; HR = 0.384 (0.179; 0.825), P = 0.01, respectively). Although differences in survival between metastases at the hilar and mediastinal locations were not significant (median survival: 74 months vs. 32 months, respectively, P = 0.75), length of survival time was associated with disease-free interval less than 12 months (median survival: 23 months vs. 94 months, P < 0.0001; HR = 3.081 (1.193; 7.957), P = 0.02).

CONCLUSION

Although LNI has an adverse effect on survival; long-term survival can be achieved in pN+ patients. Consequently, these patients should not be excluded from surgery. Systematic lymphadenectomy should be performed to obtain more accurate staging and to determine appropriate adjuvant treatment.

The frequency of tumor-infiltrating Tie-2-expressing monocytes in renal cell carcinoma: its relationship to angiogenesis and progression

OBJECTIVE

To examine the frequency of tumor-infiltrating Tie-2-expressing monocytes (TEMs) in renal cell carcinoma (RCC) and its association with microvessel density (MVD) and other clinical-pathologic features.

MATERIALS AND METHODS

This study enrolled 65 consecutive patients with RCC treated with radical nephrectomy. The frequency of tumor-infiltrating TEMs, which was defined as CD14(+) Tie-2(+) cells, was assessed using flow cytometry. MVD was measured by immunohistochemistry using anti-CD34 antibody. The association between clinicopathologic parameters, MVD, and the frequency of tumor-infiltrating TEMs in RCC was assessed.

RESULTS

High frequency of tumor-infiltrating TEMs was significantly associated with advanced stage (P = .018), positive lymph nodes (P = .013), high grade (P = .019), and metastases (P = .006). Correlation analysis revealed that the frequency of TEMs was positively correlated with MVD.

CONCLUSION

Our findings revealed a significant association between prognostic tumor features, MVD, and the frequency of tumor-infiltrating TEMs in RCC and indicated that TEMs may play an important role in angiogenesis and progression of RCC.

Ovatodiolide Targets β -Catenin Signaling in Suppressing Tumorigenesis and Overcoming Drug Resistance in Renal Cell Carcinoma

Dysregulated β-catenin signaling is intricately involved in renal cell carcinoma (RCC) carcinogenesis and progression. Determining potential β-catenin signaling inhibitors would be helpful in ameliorating drug resistance in advanced or metastatic RCC. Screening for β-catenin signaling inhibitors involved in silico inquiry of the PubChem Bioactivity database followed by TCF/LEF reporter assay. The biological effects of ovatodiolide were evaluated in 4 RCC cell lines in vitro and 2 RCC cell lines in a mouse xenograft model. The synergistic effects of ovatodiolide and sorafenib or sunitinib were examined in 2 TKI-resistant RCC cell lines. Ovatodiolide, a pure compound of Anisomeles indica, inhibited β-catenin signaling and reduced RCC cell viability, survival, migration/invasion, and in vitro cell or in vivo mouse tumorigenicity. Cytotoxicity was significantly reduced in a normal kidney epithelial cell line with the treatment. Ovatodiolide reduced phosphorylated β-catenin (S552) that inhibited β-catenin nuclear translocation. Moreover, ovatodiolide decreased β-catenin stability and impaired the association of β-catenin and transcription factor 4. Ovatodiolide combined with sorafenib or sunitinib overcame drug resistance in TKI-resistant RCC cells. Ovatodiolide may be a potent β-catenin signaling inhibitor, with synergistic effects with sorafenib or sunitinib, and therefore, a useful candidate for improving RCC therapy.

Quality of life and supportive care for patients with metastatic renal cell carcinoma

In recent years, a key issue in the management of patients with metastatic renal cell carcinoma (mRCC) has been the assessment of health-related quality of life (HRQoL), particularly following the introduction of targeted therapies that have brought significant improvements in progression-free survival and quality of life in these patients. HRQoL is becoming one of the main factors influencing choice of therapy, and HRQoL experienced during first-line treatment may affect the choice of the second-line therapy. Consequently, several trials have been conducted to evaluate the impact of approved targeted therapies for mRCC on HRQoL, and this measure is being introduced with increasing frequency in the trial design. With respect to agents used after progression on cytokines, sunitinib and temsirolimus have yielded better HRQoL scores, and sorafenib and pazopanib have shown stable HRQoL scores compared with placebo. Regarding targeted agents approved for patients who progress on a first-line tyrosine kinase inhibitor, everolimus has shown to delay and reduce the degree of Karnofsky performance status deterioration compared with placebo. Moreover, evidence obtained from these trials shows that tumor response and delay in disease progression affect HRQoL. In this article, we review the different HRQoL scales used to evaluate patients with mRCC along with the results obtained in clinical trials. Given that HRQoL is determined not only by treatment-related effects but also by mRCC symptoms and its clinical complications, the characteristics and appropriate treatment of the most commonly experienced symptoms, including anorexia, fatigue, pain, anemia, and venous thromboembolism, are also reviewed.

Evaluation of patients with metastatic renal cell carcinoma after failure of first-line treatment

The approval and use of molecular targeted agents for the first-line treatment of metastatic renal cell carcinoma (mRCC) has substantially improved the clinical outcome of patients. Although eventually all patients progress, hopes have been renewed with the approval of everolimus for patients who progress on or after treatment with tyrosine kinase inhibitors. In order to improve the prognosis for these patients, it is imperative to understand the reasons why patients with mRCC fail on first-line treatment. Currently, progression is assessed on the basis of the Response Evaluation Criteria in Solid Tumors, but it is known that targeted agents tend to cause disease stabilization rather than a significant decrease in tumor mass. Therefore, it may be time to evaluate the need to incorporate additional diagnostic methods in the assessment of disease response. Equally important is the study of the factors that determine the success or failure of second-line therapy in order to increase the chances of delivering the most effective and personalized therapy possible. In this article, we review the evidence related to the evaluation of patients with mRCC who fail on first-line treatment with targeted agents, including the systems to assess response and progression, the prognostic factors, the prognostic models that have been created based on these factors, and what is known about predictive biomarkers of disease outcome.

Novel immunotherapeutic strategies in development for renal cell carcinoma

CONTEXT

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

OBJECTIVE

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

EVIDENCE ACQUISITION

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

EVIDENCE SYNTHESIS

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

CONCLUSIONS

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

Current and future systemic treatments for renal cell carcinoma

Systemic treatment of renal cell carcinoma has changed dramatically since 2007, with the development and approval of six new agents, which target complex molecular pathways regulating tumour angiogenesis and cell proliferation and survival. These treatments have significantly improved survival times in metastatic renal cell carcinoma, but remain palliative. A number of newer agents are in clinical development, which offer theoretical advantages over existing treatments, and research methodologies are adapting with the aim of defining an individualised approach to therapy which exploits the underlying tumour biology. This review will provide an overview of current and emerging systemic treatments and how they might be integrated with surgical therapy, with a particular focus on advanced, clear cell metastatic renal cell carcinoma.

Antitumor Activity and Safety of Tivozanib (AV-951) in a Phase II Randomized Discontinuation Trial in Patients With Renal Cell Carcinoma

Purpose

The antitumor activity and safety of tivozanib, which is a potent and selective vascular endothelial growth factor receptor-1, -2, and -3 inhibitor, was assessed in patients with advanced/metastatic renal cell carcinoma (RCC).

Patients and Methods

In this phase II, randomized discontinuation trial, 272 patients received open-label tivozanib 1.5 mg/d (one cycle equaled three treatment weeks followed by a 1-week break) orally for 16 weeks. Thereafter, 78 patients who demonstrated ≥ 25% tumor shrinkage continued to take tivozanib, and 118 patients with less than 25% tumor change were randomly assigned to receive tivozanib or a placebo in a double-blind manner; patients with ≥ 25% tumor growth were discontinued. Primary end points included safety, the objective response rate (ORR) at 16 weeks, and the percentage of randomly assigned patients who remained progression free after 12 weeks of double-blind treatment; secondary end points included progression-free survival (PFS).

Results

Of 272 patients enrolled onto the study, 83% of patients had clear-cell histology, 73% of patients had undergone nephrectomy, and 54% of patients were treatment naive. The ORR after 16 weeks of tivozanib treatment was 18% (95% CI, 14% to 23%). Of the 118 randomized patients, significantly more patients who were randomly assigned to receive double-blind tivozanib remained progression free after 12 weeks versus patients who received the placebo (49% v 21%; P = .001). Throughout the study, the ORR was 24% (95% CI, 19% to 30%), and the median PFS was 11.7 months (95% CI, 8.3 to 14.3 months) in the overall study population. The most common grade 3 and 4 treatment-related adverse event was hypertension (12%).

Conclusion

Tivozanib was active and well tolerated in patients with advanced RCC. These data support additional development of tivozanib in advanced RCC.

Consolidative surgery after targeted therapy for renal cell carcinoma

Renal cell carcinoma is the most lethal of the common genitourinary neoplasms, with 30% to 40% of patients eventually dying from disease progression. Although the recent development of targeted therapies against kidney cancer has yielded substantially improved tumor response rates and progression-free survival, these agents are still not curative. The integration of systemic therapies with surgery still represents the best management for select patients with advanced disease. Specifically, consolidative surgery may play a vital role in the management of this challenging patient population. However, concerns remain regarding the potential for increased surgical morbidity complicating the integration of surgery after targeted therapy. Careful patient selection and specific precautions to increase surgical safety should be implemented.

Angiogenesis and immunity: a bidirectional link potentially relevant for the monitoring of antiangiogenic therapy and the development of novel therapeutic combination with immunotherapy

The immune system regulates angiogenesis in cancer with both pro- and antiangiogenic activities. The induction of angiogenesis is mediated by tumor-associated macrophages and myeloid-derived suppressor cells (MDSC) which produce proinflammatory cytokines, endothelial growth factors (VEGF, bFGF…), and protease (MMP9) implicated in neoangiogenesis. Some cytokines (IL-6, IL-17…) activated Stat3 which also led to the production of VEGF and bFGF. In contrast, other cytokines (IFN, IL-12, IL-21, and IL-27) display an antiangiogenic activity. Recently, it has been shown that some antiangiogenic molecules alleviates immunosuppression associated with cancer by decreasing immunosuppressive cells (MDSC, regulatory T cells), immunosuppressive cytokines (IL-10, TGFβ), and inhibitory molecules on T cells (PD-1). Some of these broad effects may result from the ability of some antiangiogenic molecules, especially cytokines to inhibit the Stat3 transcription factor. The association often observed between angiogenesis and immunosuppression may be related to hypoxia which induces both neoangiogenesis via activation of HIF-1 and VEGF and favors the intratumor recruitment and differentiation of regulatory T cells and MDSC. Preliminary studies suggest that modulation of immune markers (intratumoral MDSC and IL-8, peripheral regulatory T cells…) may predict clinical response to antiangiogenic therapy. In preclinical models, a synergy has been observed between antiangiogenic molecules and immunotherapy which may be explained by an improvement of immune status in tumor-bearing mice after antiangiogenic therapy. In preclinical models, antiangiogenic molecules promoted intratumor trafficking of effector cells, enhance endogenous anti-tumor response, and synergyzed with immunotherapy protocols to cure established murine tumors. All these results warrant the development of clinical trials combining antiangiogenic drugs and immunotherapy.

Metastatic collecting duct carcinoma of the kidney treated with sunitinib

Collecting duct carcinoma (CDC) of the kidney is a rare and aggressive malignant tumor arising from the distal collecting tubules which has been shown to have a poor response to several kinds of systemic therapy. We present a case of metastatic CDC that responded favorably to a multiple tyrosine kinase inhibitor, sunitinib, achieving a partial response in both lung and skeletal metastases. To our knowledge, this is the first report showing therapeutic activity of sunitinib against CDC. Considering these findings, it would be worthwhile prospectively investigating the role of multiple tyrosine kinase inhibitors, particularly sunitinib, in the management of metastatic CDC.

Novel functional germline variants in the VEGF receptor 2 gene and their effect on gene expression and microvessel density in lung cancer

PURPOSE

VEGF receptor 2 (VEGFR-2) plays a crucial role in mediating angiogenic endothelial cell responses via the VEGF pathway, and angiogenesis inhibitors targeting VEGFR-2 are in clinical use. As angiogenesis is a host-driven process, functional heritable variation in KDR, the gene encoding VEGFR-2, may affect VEGFR-2 function and, ultimately, the extent of tumor angiogenesis.

EXPERIMENTAL DESIGN

We resequenced KDR using 24 DNAs each from healthy Caucasian, African American, and Asian groups. Nonsynonymous genetic variants were assessed for function by phosphorylation assays. Luciferase reporter gene assays were used to examine effects of variants on gene expression. KDR mRNA and protein expression and microvessel density (MVD) were measured in non-small cell lung cancer (NSCLC) tumor samples, and matching patient DNA samples were genotyped to test for associations with variants of interest.

RESULTS

KDR resequencing led to the discovery of 120 genetic variants, of which 25 had not been previously reported. Q472H had increased VEGFR-2 protein phosphorylation and associated with increased MVD in NSCLC tumor samples. -2854C and -2455A increased luciferase expression and associated with higher KDR mRNA levels in NSCLC samples. -271A reduced luciferase expression and associated with lower VEGFR-2 levels in NSCLC samples. -906C and 23408G associated with higher KDR mRNA levels in NSCLC samples.

CONCLUSIONS

This study has defined KDR genetic variation in 3 populations and identified common variants that impact on tumoral KDR expression and vascularization. These findings may have important implications for understanding the molecular basis of genetic associations between KDR variation and clinical phenotypes related to VEGFR-2 function.

What can molecular pathology contribute to the management of renal cell carcinoma?

The incidence of renal cell carcinoma (RCC) is increasing and outcomes remain poor. One-third of patients with localized disease will relapse, and 5-year survival for patients with metastatic disease is less than 10%. No molecular test is currently available to identify which patients who have undergone 'curative' surgery will relapse, and which patients will respond to targeted therapy. Some well characterized biochemical pathways, such as those associated with von Hippel-Lindau disease, are aberrantly regulated in RCC and are associated with histological subtype, but the understanding of these pathways contributes little to the clinical management of patients with RCC. Gene expression and sequencing studies have increased our understanding of the genetic basis of the disease but have failed to establish any unified classification to improve molecular stratification or to predict which patients are likely to relapse or respond to targeted therapy. Instead, they have served to highlight that RCC is heterogeneous at histological, morphological, and molecular levels, and that novel approaches are required to resolve the complexity of RCC prognostication and prediction of treatment response.

Challenges and opportunities for converting renal cell carcinoma into a chronic disease with targeted therapies

Optimum efficacy is the primary goal for any cancer therapy, and entails controlling tumour growth and prolonging survival as far as possible. The prognosis for patients with metastatic renal cell carcinoma (mRCC) has greatly improved with the introduction of targeted therapies. This review examines the development and efficacy of targeted agents for the management of mRCC, the challenges offered by their rapid emergence, and discusses how mRCC treatment may evolve in the future. Improvements in progression-free survival and overall survival rates, observed with targeted agents, indicate that it may now be possible to change mRCC from a rapidly fatal and largely untreatable condition into a chronic disease. The major challenges to further advances in targeted therapy for mRCC include overcoming drug resistance, identifying the most effective sequence or combination of targeted agents, optimising clinical trial design and managing the cost of treatment.

Feasibility and efficacy of neoadjuvant sunitinib before nephron-sparing surgery

OBJECTIVE

To investigate efficacy of neoadjuvant tyrosine kinase-inhibitor therapy (TKI) before imperative nephron-sparing surgery (NSS), as NSS in patients with large locally advanced or centrally located tumours can be challenging, and TKI therapy might result in a reduction of primary tumour burden and increase the feasibility of NSS.

PATIENTS AND METHODS

This was a multicentre retrospective review and prospective pilot study of patients undergoing neoadjuvant sunitinib before planned NSS from February 2006 to February 2009. All patients underwent confirmatory biopsy for clear cell renal cell carcinoma. Patients received two 28-day cycles of sunitinib before NSS. Demographics/tumour characteristics, tumour response (by the Response Evaluation Criteria In Solid Tumors), outcomes and complications were analysed.

RESULTS

Twelve patients (seven men and five women; mean age 60.1 years, tumours on 14 renal units) were given TKI before NSS for imperative indications. The mean pretreatment tumour diameter was 7.1 cm; all patients had a decrease in size of the primary tumour after TKI, with a mean reduction in maximum diameter of 1.5 cm (21.1%). Four of 14 and 10 of 14 primary tumours had a partial response and stable disease after TKI. NSS was achievable in all 14 kidneys. Four patients had a concurrent metastasectomy. The mean warm ischaemia time was 22.5 min; postoperative dialysis was not required in any patients. Final pathology revealed negative tumour margins in all 14 tumours. The mean creatinine and estimated glomerular filtration rate (before/after NSS) were 1.34/1.40 mg/dL (P = 0.431) and 57.7/53.4 mL/min/1.73 m(2) (P = 0.475), respectively. At a mean follow-up of 23.9 months, 10 of the 12 patients were alive, one died from metastatic RCC and none required dialysis. Three of the 14 renal units developed delayed urinary leaks, all in patients who also received postoperative sunitinib. All leaks resolved with conservative measures.

CONCLUSIONS

Neoadjuvant TKI followed by NSS is safe and feasible, with all patients achieving a reduction in maximum tumour diameter, and with NSS being achievable with negative margins and with no requirement for postoperative dialysis. Further investigation is required.

Treatment of metastatic renal carcinoma patients with the combination of gemcitabine, capecitabine and bevacizumab at a tertiary cancer centre

OBJECTIVE

• To investigate the effect of combining gemcitabine plus capecitabine (GX) with bevacizumab (A) in patients with metastatic RCC previously treated with cytokines and targeted agents.

METHODS

• The combination of GX + A was evaluated in patients with metastatic RCC using institutional databases. • Data included demographics, previous therapies, number of metastatic sites, Memorial Sloan-Kettering Cancer Center risk stratification variables, and previous nephrectomy status. • Descriptive statistics and survival analysis were employed for data analysis.

RESULTS

• Between January 2005 and October 2008, 28 patients were identified. Mean age was 55.7 years. Fifteen (53.57%) patients had been given tyrosine kinase inhibitor (TKI) previously. Nine (32.14%) patients had clear cell histology, 10 (35.71%) patients had sarcomatoid features on histopathology, and 19 patients (67.86%) had a prior nephrectomy. • Initial treatment consisted of G (mean dose 786.07 mg/m²) every 2 weeks, X (mean dose 2.73 g/day), and A (mean dose 10 mg/kg) every 2 weeks. Median progression-free survival (PFS) was 5.9 months and the median overall survival (OS) was 10.4 months. • In patients with previous TKI therapy, median PFS was 6.2 months and median OS was 11.7 months. • In patients with sarcomatoid features, median PFS was 3.9 months and OS was 9.0 months. • Three patients discontinued one or more of the drugs because of adverse reactions.

CONCLUSIONS

• The combination of GX + A shows potential efficacy and acceptable tolerability in patients with intermediate and poor prognosis metastatic RCC. • Based on these observations, a phase II trial is now underway assessing this combination in patients with sarcomatoid RCC.

Metastatic collecting duct carcinoma of the kidney responded to sunitinib

Collecting duct carcinoma (CDC) of the kidney is a rare and aggressive malignant tumor arising from the distal collecting tubules which has been shown to have a poor response to several kinds of systemic therapy. We present a case of metastatic CDC that responded favorably to a multiple tyrosine kinase inhibitor, sunitinib, achieving a partial response in both lung and skeletal metastases. To our knowledge, this is the first report showing therapeutic activity of sunitinib against CDC. Considering these findings, it would be worthwhile prospectively investigating the role of multiple tyrosine kinase inhibitors, particularly sunitinib, in the management of metastatic CDC.

Interleukin-8 mediates resistance to antiangiogenic agent sunitinib in renal cell carcinoma

The broad spectrum kinase inhibitor sunitinib is a first-line therapy for advanced clear cell renal cell carcinoma (ccRCC), a deadly form of kidney cancer. Unfortunately, most patients develop sunitinib resistance and progressive disease after about 1 year of treatment. In this study, we evaluated the mechanisms of resistance to sunitinib to identify the potential tactics to overcome it. Xenograft models were generated that mimicked clinical resistance to sunitinib. Higher microvessel density was found in sunitinib-resistant tumors, indicating that an escape from antiangiogenesis occurred. Notably, escape coincided with increased secretion of interleukin-8 (IL-8) from tumors into the plasma, and coadministration of an IL-8 neutralizing antibody resensitized tumors to sunitinib treatment. In patients who were refractory to sunitinib treatment, IL-8 expression was elevated in ccRCC tumors, supporting the concept that IL-8 levels might predict clinical response to sunitinib. Our results reveal IL-8 as an important contributor to sunitinib resistance in ccRCC and a candidate therapeutic target to reverse acquired or intrinsic resistance to sunitinib in this malignancy.

FDA drug approval summary: bevacizumab plus interferon for advanced renal cell carcinoma

On July 31, 2009, the U.S. Food and Drug Administration granted approval for the use of bevacizumab (Avastin(R); Genentech, Inc., South San Francisco, CA) in combination with interferon (IFN)-alpha2a for the treatment of patients with metastatic renal cell carcinoma. The approval was primarily based on results from a randomized, double-blind, placebo-controlled clinical trial. The primary efficacy endpoint, progression-free survival (PFS), was assessed by investigators and by an independent review committee (IRC) blinded to treatment assignment. In total, 649 patients (bevacizumab plus IFN, 327; placebo plus IFN, 322) were enrolled. The median PFS times, by investigator determination, were 10.2 months for the bevacizumab plus IFN arm and 5.4 months for the placebo plus IFN arm (hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.49-0.72; p < .0001). The IRC analysis of 569 patients with available radiographs yielded similar results (median PFS time, 10.4 months versus 5.5 months; HR, 0.57; 95% CI, 0.45-0.72; p < .0001). There was no survival advantage (HR, 0.86; 95% CI, 0.72-1.04; p = .13). Support for the above results was provided by summarized results of a North American cooperative group study of bevacizumab plus IFN-alpha2b versus IFN-alpha2b alone. The median PFS times were 8.4 months versus 4.9 months in favor of the bevacizumab combination. There was no survival advantage. In the reviewed trial, serious adverse events and National Cancer Institute Common Terminology Criteria for Adverse Events grade >/=3 adverse events were reported more frequently in bevacizumab-treated patients (31% versus 19% and 63% versus 47%, respectively). The most common bevacizumab-related toxicities were bleeding/hemorrhage, hypertension, proteinuria, and venous or arterial thromboembolic events.

Recent developments in the pathology of renal tumors: morphology and molecular characteristics of select entities

CONTEXT

Renal cell carcinoma is a heterogeneous group of tumors with distinct histopathologic features, molecular characteristics, and clinical outcome. These tumors can be sporadic as well as familial or associated with syndromes. The genetic abnormalities underlying these syndromes have been identified and were subsequently found in corresponding sporadic renal tumors.

OBJECTIVE

To review the recent molecular and genetic advancements relating to sporadic and familial renal carcinomas as well as those related to Xp11.2 translocation-associated renal cell carcinoma and renal medullary carcinoma.

DATA SOURCES

Literature review, personal experience, and material from the University of Chicago.

CONCLUSIONS

Molecular genetic diagnostic techniques will continue to introduce new biomarkers that will aid in the differential diagnosis of difficult cases. The identification of specific signaling pathways that are defective in certain renal tumors also makes possible the development of new therapies that selectively target the aberrant activity of the defective proteins.