Genetic basis of kidney cancer: a model for developing molecular-targeted therapies

Englerins: A Comprehensive Review

In the decade since the discovery of englerin A (1) and its potent activity in cancer models, this natural product and its analogues have been the subject of numerous chemical, biological, and preclinical studies by many research groups. This review summarizes published findings and proposes further research directions required for entry of an englerin analogue into clinical trials for kidney cancer and other conditions.

Modification of the tumor microenvironment as a novel target of renal cell carcinoma therapeutics

To move forward with immunotherapy, it is important to understand how the tumor microenvironment generates systemic immunosuppression in patients with renal cell carcinoma (RCC) as well as in patients with other types of solid tumors. Even though antigen discovery in RCC has lagged behind melanoma, recent clinical trials have finally authenticated that RCC is susceptible to vaccine-based therapy. Furthermore, judicious coadministration of cytokines and chemotherapy can potentiate therapeutic responses to vaccine in RCC and prolong survival, as has already proved possible for melanoma. Although high-dose interleukin 2 immunotherapy has been superseded as first-line therapy for RCC by promiscuous receptor tyrosine kinase inhibitors (rTKIs) such as sunitinib, sunitinib itself is a potent immunoadjunct in animal tumor models. A reasonable therapeutic goal is to unite antiangiogenic strategies with immunotherapy as first-line therapy for RCC. This strategy is equally appropriate for testing in all solid tumors in which the microenvironment generates immunosuppression. A common element of RCC and pancreatic, colon, breast, and other solid tumors is large numbers of circulating myeloid-derived suppressor cells (MDSCs), and because MDSCs elicit regulatory T cells rather than vice versa, gaining control over MDSCs is an important initial step in any immunotherapy. Although rTKIs like sunitinib have a remarkable capacity to deplete MDSCs and restore normal T-cell function in peripheral body compartments such as the bloodstream and the spleen, such rTKIs are effective only against MDSCs, which are engaged in phospho-STAT3-dependent programming (pSTAT3+). Unfortunately, rTKI-resistant pSTAT3- MDSCs are especially apt to arise within the tumor microenvironment itself, necessitating strategies that do not rely exclusively on STAT3 disruption. The most utilitarian strategy to gain control of both pSTAT3+ and pSTAT3- MDSCs may be to exploit the natural differentiation pathway, which permits MDSCs to mature into tumoricidal macrophages (TM1) via such stimuli as Toll-like receptor agonists, interferon γ, and CD40 ligation. Overall, this review highlights the mechanisms of immune suppression used by the different regulatory cell types operative in RCC as well as other tumors. It also describes the different therapeutic strategies to overcome the suppressive nature of the tumor microenvironment.

Robotic partial nephrectomy: current technique and outcomes

Over the past decade, management of the T1 renal mass has focused on nephron-sparing surgery. Robotic partial nephrectomy has played an increasing role in the technique of preserving renal function by decreasing warm ischemia time, as well as optimizing outcomes of hemorrhage and fistula. Robot-assisted partial nephrectomy is designed to provide a minimally-invasive nephron-sparing surgical option utilizing reconstructive capability, decreasing intracorporeal suturing time, technical feasibility and safety. Ultimately, its benefits are resulting in its dissemination across institutions. Articulated instrumentation and three-dimensional vision facilitate resection, collecting system reconstruction and renorrhaphy, leading to decreased warm ischemia time while preserving oncological outcomes. The aim of the present review was to present our surgical sequence and technique, as well as review the current status of robot-assisted partial nephrectomy.

Description of a multicenter safety checklist for intraoperative hemorrhage control while clamped during robotic partial nephrectomy

Background

The adoption of robotic assistance has contributed to the increased utilization of partial nephrectomy for the management of renal tumors. However, partial nephrectomy can be technically challenging because of intraoperative hemorrhage, which limits the ability to identify the tumor margin and may necessitate the conversion to open surgery or radical nephrectomy. To our knowledge, a comprehensive safety checklist does not exist to guide surgeons on the management of hemorrhage during robotic partial nephrectomy. We developed such an safety checklist based on the cumulative experiences of high volume robotic surgeons.

Methods

A treatment safety checklist for the management of hemorrhage during robotic partial nephrectomy was collaboratively developed based on prior experiences with intraoperative hemorrhage during robotic partial nephrectomy.

Results

Reducing the risk of hemorrhage during robotic partial nephrectomy begins with reviewing the preoperative imaging for renal vasculature and tumor anatomy, with a focus on accessory vessels and renal tumor proximity to the renal hilum. During hilar exposure, an attempt is made to identify additional accessory renal arteries. The decision is then made on whether to clamp the hilum (artery +/- vein). If bleeding is encountered during resection, management is based on whether the bleeding is suspected to be arterial or from venous backbleeding. Operative maneuvers that may increase the chance of success are highlighted in safety checklists for arterial and venous bleeding.

Conclusions

Safely performing robotic partial nephrectomy is dependent on attention to prevention of hemorrhage and rapid response to the challenge of intraoperative bleeding. Preparation is essential for maximizing the chance of success during robotic partial nephrectomy.

Genetic pathways involved in carcinogenesis of clear cell renal cell carcinoma: genomics towards personalized medicine

What's known on the subject? and What does the study add? Sporadic clear cell Renal Cell Carcinoma (ccRCC) is dominated by nutations of the VHL gene located on chromosome 3p in up to 90% of cases. This gene plays a critical role in hypoxia response, including stimulation of neoangiogenesis. Since 2006, anti-angiogenci therapies targeting this pathway are used in metastatic patients with objective response rate as high as 45%. However, these treatments don't target directly the tumour cell, allowing the potential for disease progession despite treatment. Large scale analysis recently showed that substantial genetic heterogeneity exists in ccRCC. Associated alterations include genes implicated in methylation regulation in 15% of cases, underlying the importance of epigenetic modifications, and truncating mutations in chromatin remodelling complex PRMB1 in 41% of cases. Systematic screening of these tumours is a way to fully determine the somatic genetic architecture of RCC in order to improve tumour classification, to develop prognostic and predictive markers and to target new molecular pathways involved in carcinogenesis. • A critical review is provided of the recent progress in oncogenetics applied to renal cell carcinoma (RCC) by highlighting our current understanding of the genetic pathways involved in carcinogenesis and its current and future clinical application. • RCC comprises a model of translational research because an improved understanding of molecular pathways has led to several targeted therapy options for patients with metastatic RCC. • Alteration of the product of the Von Hippel-Lindau gene/hypoxia inductible factor/vascular endothelial growth factor pathway is well characterized in carcinogenesis and is the target of the current therapies for metastatic RCC. • However, substantial genetic heterogeneity exists in this cancer and current treatments do not target directly the tumour cell. • Improving overall survival still remains a challenging objective but, currently, there is a lack of prognostic and predictive biomarkers for response to treatment. • Further information is awaited from the genomic approach to tumour classification, prognostic markers and predictive indicators of response to the treatment, as well as the personal susceptibility of developing RCC when exposed to risk factors. • Recent technological developments, such as large-scale analysis and high-speed sequencing, will allow the systematic screening of tumours to fully determine the somatic genetic architecture of RCC.

Chromophobe renal cell cancer--review of the literature and potential methods of treating metastatic disease

Chromophobe renal cell carcinoma (ChRCC) is a subtype of renal cell carcinoma (RCC). ChRCC is diagnosed mainly in 6th decade of life. An incidence of ChRCC is similar in both men and woman. Eighty six percent of ChRCCs cases are diagnosed in stage 1 or 2. Prognosis of ChRCC is better than in other types of RCC. Five- and 10-year disease free survival (DFS) for ChRCC was 83.9% and 77.9%, respectively. Expression of immunohistological markers: cytokeratins (CK), vimentin, epithelial membrane antigen (EMA), CD10 could be potentially helpful in diagnosis of different subtypes of RCC. From all conventional RCC, CD 117 was detected (overexpression) in membrane of cells ChRCC.Overexpression of CD117 on cellular membranes of ChRCC could be a potential target for kinase inhibitors like: imatinib, dasatinib, nilotinib. The potential targets for other kinase inhibitors (sunitinib and sorafenib) in ChRCC seem to be VEGFR and PDGFR. On the basis for formulating research hypotheses which should be verified by prospective studies.

Patterns of gene expression and copy-number alterations in von-hippel lindau disease-associated and sporadic clear cell carcinoma of the kidney

Recent insights into the role of the von-Hippel Lindau (VHL) tumor suppressor gene in hereditary and sporadic clear-cell renal cell carcinoma (ccRCC) have led to new treatments for patients with metastatic ccRCC, although virtually all patients eventually succumb to the disease. We performed an integrated, genome-wide analysis of copy-number changes and gene expression profiles in 90 tumors, including both sporadic and VHL disease-associated tumors, in hopes of identifying new therapeutic targets in ccRCC. We identified 14 regions of nonrandom copy-number change, including 7 regions of amplification (1q, 2q, 5q, 7q, 8q, 12p, and 20q) and 7 regions of deletion (1p, 3p, 4q, 6q, 8p, 9p, and 14q). An analysis aimed at identifying the relevant genes revealed VHL as one of three genes in the 3p deletion peak, CDKN2A and CDKN2B as the only genes in the 9p deletion peak, and MYC as the only gene in the 8q amplification peak. An integrated analysis to identify genes in amplification peaks that are consistently overexpressed among amplified samples confirmed MYC as a potential target of 8q amplification and identified candidate oncogenes in the other regions. A comparison of genomic profiles revealed that VHL disease-associated tumors are similar to a subgroup of sporadic tumors and thus more homogeneous overall. Sporadic tumors without evidence of biallelic VHL inactivation fell into two groups: one group with genomic profiles highly dissimilar to the majority of ccRCC and a second group with genomic profiles that are much more similar to tumors with biallelic inactivation of VHL.

Bevacizumab: direct anti-VEGF therapy in renal cell carcinoma

Bevacizumab, in combination with IFN, is approved in the EU as first-line therapy for advanced and/or metastatic renal cell carcinoma (mRCC). Data from Avastin and Roferon in Renal Cell Carcinoma [BO17705] (AVOREN), a Phase III trial, demonstrated that bevacizumab plus IFN significantly improves progression-free survival and response rate in patients with previously untreated mRCC compared with IFN plus placebo. Furthermore, bevacizumab plus IFN is well tolerated and has a predictable and well-established tolerability profile; reducing the dose of IFN, when necessary, can effectively manage IFN-related side effects without compromising efficacy. The rapid evolution of options for RCC therapy means that the optimal use of available agents to maximize patient benefit is not currently well defined. Combination regimens and sequencing of agents are both being investigated to maximize future outcomes, with bevacizumab playing a key role in first-line regimens. Trials over the next 5 years will guide clinical practice, but bevacizumab plus IFN is currently a standard first-line option for mRCC.

Targeted therapies in the management of renal cell carcinoma: role of bevacizumab

Bevacizumab (10 mg/kg every 2 weeks), in combination with interferon alpha-2a (IFN), is an effective option for first-line therapy for advanced and/or metastatic renal cell carcinoma (RCC). Two phase III trials clearly show significant improvements in progression-free survival and response rate in patients with treatment-naïve metastatic RCC receiving bevacizumab combined with IFN compared with IFN. The dose of IFN, which was initiated at 9 MIU 3 times a week in these trials, can be reduced to effectively manage IFN-related side effects without compromising the efficacy of bevacizumab plus IFN. Bevacizumab has good tolerability with manageable side effects, both alone and in combination with other agents; the tolerability profile of bevacizumab in combination with IFN is consistent with the well-characterized and well-established profiles of these therapies. The tolerability of bevacizumab combined with IFN and the flexibility to manage IFN-related side effects are important considerations when selecting first-line therapy. With a number of options now available for RCC therapy, optimizing their use is a key consideration in improving patient benefit.

Pathologic concordance of sporadic synchronous bilateral renal masses

OBJECTIVES

To review the collective experience evaluating pathologic concordance rates of sporadic bilateral synchronous renal tumors reported in the Surveillance, Epidemiology, and End Results (SEER) database and the published English literature and treated at Fox Chase Cancer Center; specifically, to analyze concordance rates of malignant versus benign disease, histologic type, tumor stage, and nuclear grade.

METHODS

We reviewed the SEER database, the published English language literature, and our own institutional tumor registry to identify all cases of sporadic, synchronous localized (cT1-3N0M0) bilateral renal masses. Malignant and benign concordance rates were defined as agreement of any benign or malignant tumor type bilaterally. Histologic concordance was defined as bilateral histologic agreement. Tumors with mixed histologies were discordant unless all patterns were identical bilaterally. Nuclear grades were concordant if bilateral tumors were either "high" grade or "low" grade.

RESULTS

The malignant concordance rate in the SEER data was 99% (273 of 274), and benign concordance was 0 (0 of 1). In the published literature and Fox Chase Cancer Center series, malignant concordance rates ranged from 84% to 95%, whereas benign concordance ranged from 39% to 67%. The SEER data revealed a histologic concordance rate of 93% (256 of 274), and nuclear grade concordance was 85% (88 of 103).

CONCLUSIONS

These data demonstrate that in cases of bilateral sporadic localized synchronous renal masses, a diagnosis of ipsilateral renal cell carcinoma is associated with contralateral renal cell carcinoma in the vast majority of patients, whereas ipsilateral benign pathology is associated with contralateral benign disease at a substantially lower rate. Histologic concordance is similarly high, meaning most cases of clear cell or papillary tumors ipsilaterally are concordant in the contralateral kidney. Concordance rates of nuclear grade were slightly lower. These data are important when counseling and managing patients with bilateral synchronous sporadic renal tumors.