Brain metastases from renal cell carcinoma. Should we change the current standard?

18F-DCFPyL PET/CT in Metastatic Renal Cell Carcinoma

Targeted molecular imaging with positron emission tomography (PET) utilize chemical ligands is a peptide that specifically targets a receptor of interest. Prostate specific membrane antigen (PSMA) is substantially upregulated in prostate cancer but is also expressed in the neovascular tissue of several malignancies, including renal cell carcinoma (RCC). Radiolabeled peptide targets for PSMA may be helpful in detecting metastatic RCC lesions. This teaching case provides an insight incidental detection of RCC metastatic disease with PSMA targeted PET and explores potential in deliberate evaluation of RCC with PSMA targeted tracers.

Prognostic Factors and Current Treatment Strategies for Renal Cell Carcinoma Metastatic to the Brain: An Overview

Renal cell carcinoma (RCC) is one of primary cancers that frequently metastasize to the brain. Brain metastasis derived from RCC has the propensity of intratumoral hemorrhage and relatively massive surrounding edema. Moreover, it confers a grim prognosis in a great percentage of cases with a median overall survical (mOS) around 10 months. The well-recognized prognostic factors for brain metastatic renal cell carcinoma (BMRCC) are Karnofsky Performance Status (KPS), the number of brain metastasis (BM), the presence of a sarcomatoid component and the presence of extracranial metastasis. Therapeutic strategies are multimodal and include surgical resection, radiotherapy, such as stereotactic radiosurgery due to the radioresistance of RCC and systemic strategies with tyrosin kinase inhibitors (TKI) or Immune checkpoint inhibitors (ICI) whose efficacy is not well-established in this setting of patients due to their exclusion from most clinical trials. To date, in case of positive prognostic factors and after performing local radical therapies, such as complete resection of BM or stereotactic radiosurgery (SRS), the outcome of these patients significantly improves, up to 33 months in some patients. As a consequence, tailored clinical trials designed for BMRCC are needed to define the correct treatment strategy even in this poor prognostic subgroup of patients.

The prognostic value of ephrin type-A2 receptor and Ki-67 in renal cell carcinoma patients: An Immunohistochemical and Bioinformatical Approach; A STROBE - compliant article

Patients with renal cell carcinoma (RCC), the most common malignant renal epithelial tumor, usually present with advanced disease and unpredicted clinical behavior. The receptor tyrosine kinase, ephrin type-A receptor 2 (EphA2) was found to be overexpressed in several malignancies and its expression was found to be associated with poor prognostic features.Our study is an observational study with the aim of investigating the prognostic value of EphA2 in RCC patients and its association with clinicopathological parameters as well as Ki-67 expression, which is a well-known proliferative and prognostic marker in RCC.EphA2 and Ki-67 immunohistochemical staining was performed on whole sections representative of 50 patients diagnosed with primary RCC from 2013 to 2018. In addition, the association between EphA2 mRNA expression and clinicopathological parameters as well as the patients' outcome was also evaluated using two large publicly available databases.Our results showed a significant association between EphA2 immunohistochemical expression and tumor size, nuclear grade, tumor stage, patients' outcome and Ki-67 expression (P < .05 for all). The same trend was also observed with EphA2 mRNA expression using larger patients' cohorts in 2 publicly available databases. Notably, EphA2 protein expression showed higher levels of co-expression with the proliferative marker Ki-67.Our results suggested that higher expression of EphA2 and Ki-67 in tumor tissues predicts a locally aggressive behaviour and poor outcome of patients with RCC. Moreover, our results give a rationale for the potential benefits of using novel therapeutic strategies with the aim of targeting EphA2 receptor in RCC patients that might help in improving their outcome.

The circular RNA hsa-circ-0072309 plays anti-tumour roles by sponging miR-100 through the deactivation of PI3K/AKT and mTOR pathways in the renal carcinoma cell lines

Aims: To explore the roles and regulatory mechanisms of the circular RNA (circRNA)-hsa-circ-0072309 in CAKI-1 and ACHN cells. Methods: CAKI-1 and ACHN cells were transfected with hsa-circ-0072309 overproduction vector (circRNA) and microRNA-100 (miR-100) mimic or the corresponding controls. Cell viability was detected with the CCK-8. The protein expression levels of p53, c-Myc, cleaved-caspase-3/9, matrix metalloproteinase (MMP)-2/9, vimentin, AKT, PI3K and mTOR were individually determined through western blot. qRT-PCR was used to examine the expressions of hsa-circ-0072309 and miR-100. The apoptotic rate and the migration or invasion rates were separately determined by the annexin v-FITC/PI with a flow cytometer and modified two-chamber migration assay or millicell hanging cell culture. Results: The hsa-circ-0072309 was poorly expressed in tumor tissue. Abundant hsa-circ-0072309 induced the inhibitions of cell proliferation, migration and invasion, as well as the PI3K/AKT and the mTOR cascades but enhancement of apoptosis. circRNA stimulated the down-regulation of miR-100, which was low-expressed in tumour tissue and whose overproduction abolished the impacts of circRNA on these elements mentioned above. Conclusion: The hsa-circ-0072309 played anti-tumour roles by targeting miR-100 by blocking the PI3K/AKT and mTOR cascades in the CAKI-1 and ACHN cell lines.

Brain Metastasis From Renal-Cell Carcinoma: An Institutional Study

BACKGROUND

Brain metastases (BM) are frequently observed in advanced renal-cell carcinoma (RCC). Historically these individuals have been excluded from clinical trials, but recently, with better local control, many can receive aggressive therapy after treatment. We evaluate our single-institution experience over various treatment eras.

PATIENTS AND METHODS

Patients undergoing evaluation for RCC BM from 2001 to 2018 were identified from our institutional database. Clinical notes, demographics, comorbidities, histology, central nervous system (CNS) treatments, systemic therapy, and outcomes were reviewed. Overall survival (OS) and CNS recurrence-free survival (RFS) were evaluated by the Kaplan-Meier method. Cumulative incidence was evaluated using a competing risk model.

RESULTS

We identified 158 patients with RCC BM, of whom 94.4% had clear-cell RCC, and 90.6% had extracranial metastases at diagnosis. Of these patients, 94 (60%) developed RCC BM over time, while 46 (29.1%) had RCC BM at initial presentation. Clinical symptoms were noted in 81.9% of patients. The median OS after diagnosis of RCC BM was 8.4 months, with a 3-year OS of 28.2%. The median CNS RFS was 8.5 months overall; however, those with one and more than one lesion had median CNS RFS of 12.4 and 6 months, respectively (P < .001).

CONCLUSION

The majority of RCC patients with BM are symptomatic and had prior metastatic disease that progressed to the brain. Those with a solitary RCC BM are less likely to develop CNS recurrence after local therapy and are ideal candidates for enrollment onto clinical trials.

Do renal cell carcinoma patients with brain metastases still need nephrectomy?

PURPOSE

To evaluate the value of nephrectomy for survival prognosis in renal cell carcinoma (RCC) patients with brain metastases (BM).

METHODS

There were 933 RCC patients diagnosed with BM in SEER database from 2010 to 2014. Kaplan-Meier method and Cox regression model were used to analyze the survival prognosis. The effect of nephrectomy on overall survival (OS) was analyzed by propensity score matching. The competitive risk model was performed to explore the relationship between surgery and cancer-specific survival (CSS), and the nomogram visualization model was established by R language to predict survival rate.

RESULTS

BM accounted for 1.5% of newly diagnosed RCC patients and 11.1% of M1 stage patients with the median survival time of 5 months (95% CI 4.5-5.5). Age 45-65 years, tumor diameter > 10 cm and histologic type of clear cell renal cell carcinoma (ccRCC) were high risk factors for BM in RCC patients. Age, N stage, lung metastasis and nephrectomy were independent prognostic factors. Nephrectomy was beneficial for both OS and CSS for the analysis of 216 patients successfully matched. The nomogram model has a certain value in predicting the survival rate with the internal verification c-index of 0.727.

CONCLUSIONS

Patients with high risk of BM (age 45-65 years, tumor diameter > 10 cm, histologic type of ccRCC) should emphasize brain imaging screening during follow-up. Nephrectomy may bring survival advantages for RCC patients with BM. Nomogram model based on nephrectomy can helps predicting the 1-, 2- and 3-year survival rates.

A comprehensive review of the role of immune checkpoint inhibitors in brain metastasis of renal cell carcinoma origin

The contribution of renal cell carcinoma (RCC) to brain metastases (BM) reaches 7-13%. These patients have limited survival with local control and targeted therapies. Immune checkpoint inhibitors (ICI) revolutionized the treatment landscape of RCC but commonly excluded BM patients from their pivotal trials. The daily clinical practice often imposes the use of ICI in RCC patients with BM in view of the promising survival times and durations of response. Only small prospective trials have included BM patients but rarely reported on the efficacy or safety of ICI in this subgroup. The available data is limited to small retrospective and prospective series that have shown comparable efficacy to that of the pivotal trials. In this review, we will discuss the biological rationale and potential concerns for the use of ICI in BM RCC. Furthermore, we will summarize BM subgroup data from the prospective and retrospective series of ICI in RCC as well as the use of cranial radiation and ICI.

Oridonin enhances the cytotoxicity of 5-FU in renal carcinoma cells by inducting necroptotic death

BACKGROUND

5-fluorouracil (5-FU) is widely used for the treatment of renal carcinoma. However, drug resistance remains the reason for failure of chemotherapy. Oridonin, extracted from Chinese herb medicine, displays anti-tumor effect in several types of cancer. Whether oridonin could enhance the effect of 5-FU in renal carcinoma has not been studied.

METHODS

786-O cells were used in the current study. Cell death was measured by MTT assay or live- and dead-cell staining assay. Glutathione (GSH) level was examined by ELISA. Necroptosis was identified by protein levels of receptors interaction protein-1 (RIP-1) and RIP-3, lactate dehydrogenase (LDH) and high mobility group box-1 protein (HMGB1) release, and poly [ADP-ribose] polymerase-1 (Parp-1) activity. Using a xenograft assay in nude mice, we tested the anti-tumor effects of the oridonin combined with 5-FU.

RESULTS

5-FU only induced apoptosis in 786-O cells. Oridonin activated both apoptosis and necroptosis in 786-O cells. Oridonin-induced necroptosis was reversed by addition of GSH or its precursorN-acetylcysteine (NAC). Oridonin-induced necroptosis was associated by activated JNK, p38, and ERK in 786-O cells, which were abolished by GSH or NAC treatment. However, JNK, p38, and ERK inhibitors showed no effect on oridonin induced-cell death. GSH or NAC treatment partly abolished the synergistic effects of oridonin and 5-FU on cell death. Oridonin enhanced the cytotoxicity of 5-FU both in vitro and in vivo.

CONCLUSION

Oridonin enhances the cytotoxicity of 5-FU in renal cancer cells partially through inducing necroptosis, providing evidence of using necroptosis inducers in combination with chemotherapeutic agents for cancer treatment.

miR-502-mediated histone methyltransferase SET8 expression is associated with clear cell renal cell carcinoma risk

Genetic variants may affect the interactions between microRNAs (miRNAs/miRs) and their target genes by modulating their binding affinity or by creating, or destroying a miRNA-binding site. SET domain containing (lysine methyltransferase) 8 (SET8) is the sole lysine methyltransferase that catalyzes the monomethylation of histone H4 lysine 20, and is associated with tumor growth, invasion and metastasis. In the present study, the rs16917496 polymorphism within the miR-502 binding site of the SET8 mRNA 3' untranslated region (3'UTR) in patients with clear cell renal cell carcinoma (ccRCC) and healthy controls was genotyped. The SET8 CC genotype was associated with a decreased ccRCC risk compared with the CT [P=0.003; odds ratio (OR)=0.318; 95% confidence interval (CI), 0.146-0.691], TT (P=0.011; OR=0.402; 95% CI, 0.197-0.819) and CT+TT (P=0.004; OR=0.370; 95% CI, 0.186-0.736) genotypes. The SET8 CC genotype was associated with reduced SET8 expression based on immunostaining of ccRCC tissue. Low SET8 protein levels were negatively associated with tumor-node-metastasis staging in patients with ccRCC according to the size of tumor and lymph node metastases. SET8-knockdown inhibited renal carcinoma 786-O cell proliferation, migration and invasion. c-Myc and matrix metalloproteinase-7 mRNA expression were downregulated upon SET8-knockdown in renal carcinoma 786-O cells. These data indicated that SET8 may be a functional tumor promoter and that its activation, which is partially regulated by changing the miR-502 and SET8 3'UTR binding affinity, may serve an important role in ccRCC development.

Prognostic Factors for Survival of Patients With Synchronous or Metachronous Brain Metastasis of Renal Cell Carcinoma

INTRODUCTION

We evaluated the oncological outcomes of synchronous or metachronous brain metastasis (BM) of metastatic renal cell carcinoma (RCC) according to clinicopathologic factors.

PATIENTS AND METHODS

Patients with metastatic RCC (n = 93) with synchronous and metachronous BM were retrospectively identified. We analyzed patients and tumor characteristics, treatment methods, prognostic factors, BM progression, and overall survival (OS).

RESULTS

Seventy-six patients (81.7%) received local therapy (stereotactic radiosurgery [60.2%], radiation therapy [22.6%], and neurosurgery [10.8%]), and 54 patients (58.1%) were treated with systemic medical therapy. In multivariable analysis, poor Memorial Sloan-Kettering Cancer Center (MSKCC) risk (hazard ratio [HR] 3.672; 95% confidence interval [CI], 1.441-9.36; P = .0064), sarcomatoid component (HR 4.264; 95% CI, 2.062-8.820; P = .0001), and multiple BMs (HR 2.838; 95% CI, 1.690-4.767; P = .0001) were prognostic indicators of a poorer OS outcome. Local (HR 0.436; 95% CI, 0.237-0.802; P = .0076) and systemic treatment (HR 0.322; 95% CI, 0.190-0.548; P < .0001) were independent factors for a better OS. Although OS from initial RCC diagnosis in patients with metachronous BM was better than that for patients with synchronous BM, there were no differences found between synchronous and metachronous patients in terms of BM progression and OS after the diagnosis of BM.

CONCLUSIONS

Poor MSKCC risk, sarcomatoid component of histology, and multiple BMs are prognostic indicators for poor OS in patients with BM from metastatic RCC. Systemic and/or local treatment improves the OS. Because the type of BM, synchronous or metachronous, does not influence BM progression or the OS outcome, routine evaluation for BM is not recommended.

Sunitinib Possible Sex-Divergent Therapeutic Outcomes

Sunitinib is a tyrosine kinase inhibitor used for the treatment of renal cell carcinoma and metastatic brain tumors. Preclinical pharmacokinetic studies have shown higher sunitinib hepatic and brain exposure in female mice and higher sunitinib kidney concentrations in male mice. We explored whether sex-divergent tissue pharmacokinetics may anticipate sex-divergent therapeutic and toxicology responses in male and female patients. The review of the available scientific literature identified case reports, case series reports, clinical trials, and other studies associating sex with sunitinib outcomes. The results suggest male patients may respond better to renal cell carcinoma treatment and female patients may have better brain tumor treatment outcomes but a higher incidence of adverse events. Although more high-quality evidence is needed, these results, as anticipated by the preclinical data, may indicate possible sunitinib sex-divergent therapeutic outcomes in patients. In addition, we propose the systematic analysis of sex-based outcomes in clinical trial reports and their inclusion and review in the ethics committees and review boards to prevent, amongst others, patient burden in upcoming clinical trials.

Identifying Significant Features in Cancer Methylation Data Using Gene Pathway Segmentation

In order to provide the most effective therapy for cancer, it is important to be able to diagnose whether a patient's cancer will respond to a proposed treatment. Methylation profiling could contain information from which such predictions could be made. Currently, hypothesis testing is used to determine whether possible biomarkers for cancer progression produce statistically significant results. However, this approach requires the identification of individual genes, or sets of genes, as candidate hypotheses, and with the increasing size of modern microarrays, this task is becoming progressively harder. Exhaustive testing of small sets of genes is computationally infeasible, and so hypothesis generation depends either on the use of established biological knowledge or on heuristic methods. As an alternative machine learning, methods can be used to identify groups of genes that are acting together within sets of cancer data and associate their behaviors with cancer progression. These methods have the advantage of being multivariate and unbiased but unfortunately also rapidly become computationally infeasible as the number of gene probes and datasets increases. To address this problem, we have investigated a way of utilizing prior knowledge to segment microarray datasets in such a way that machine learning can be used to identify candidate sets of genes for hypothesis testing. A methylation dataset is divided into subsets, where each subset contains only the probes that relate to a known gene pathway. Each of these pathway subsets is used independently for classification. The classification method is AdaBoost with decision trees as weak classifiers. Since each pathway subset contains a relatively small number of gene probes, it is possible to train and test its classification accuracy quickly and determine whether it has valuable diagnostic information. Finally, genes from successful pathway subsets can be combined to create a classifier of high accuracy.

Stereotactic Radiosurgery for Renal Cancer Brain Metastasis: Prognostic Factors and the Role of Whole-Brain Radiation and Surgical Resection

Background. Renal cell carcinoma is a frequent source of brain metastasis. We present our consecutive series of patients treated with Stereotactic Radiosurgery (SRS) and analyse prognostic factors and the interplay of WBRT and surgical resection. Methods. This is a retrospective study of 66 patients with 207 lesions treated with the Cyberknife radiosurgery system in our institution. The patients were followed up with imaging and clinical examination 1 month and 2-3 months thereafter for the brain metastasis. Patient, treatment, and outcomes characteristics were analysed. Results. 51 male (77.3%) and 15 female (22.7%) patients, with a mean age of 58.9 years (range of 31–85 years) and a median Karnofsky Performance Status (KPS) of 90 (range of 60–100), were included in the study. The overall survival was 13.9 months, 21.9 months, and 5.9 months for the patients treated with SRS only, additional surgery, and WBRT, respectively. The actuarial 1-year Local Control rates were 84%, 94%, and 88% for SRS only, for surgery and SRS, and for WBRT and additional SRS, respectively. Conclusions. Stereotactic radiosurgery is a safe and effective treatment option in patients with brain metastases from RCC. In case of a limited number of brain metastases, surgery and SRS might be appropriate.

Renal cell carcinoma: Review of etiology, pathophysiology and risk factors

BACKGROUND AND AIMS

The global incidence of renal cell cancer is increasing annually and the causes are multifactorial. Early diagnosis and successful urological procedures with partial or total nephrectomy can be life-saving. However, only up to 10% of RCC patients present with characteristic clinical symptoms. Over 60% are detected incidentally in routine ultrasound examination. The question of screening and preventive measures greatly depends on the cause of the tumor development. For the latter reason, this review focuses on etiology, pathophysiology and risk factors for renal neoplasm.

METHODS

A literature search using the databases Medscape, Pubmed, UpToDate and EBSCO from 1945 to 2015.

RESULTS AND CONCLUSIONS

Genetic predisposition/hereditary disorders, obesity, smoking, various nephrotoxic industrial chemicals, drugs and natural/manmade radioactivity all contribute and enviromental risks are a serious concern in terms of prevention and the need to screen populations at risk. Apropos treatment, current oncological research is directed to blocking cancer cell division and inhibiting angiogenesis based on a knowledge of molecular pathways.

High EphA2 protein expression in renal cell carcinoma is associated with a poor disease outcome

The receptor tyrosine kinase, ephrin type-A receptor 2 (EphA2), is normally expressed at sites of cell-to-cell contact in adult epithelial tissues, however, recent studies have shown that it is also overexpressed in various types of epithelial carcinomas, with the greatest level of EphA2 expression observed in metastatic lesions. In the present study, the association between the expression of EphA2 and the outcome of RCC patients was assessed. The high expression level of EphA2 was identified by log-rank test for a statistically significant prediction of the RCC outcome. In an overall multivariate analysis, the high expression level of EphA2 was identified as an independent predictor of RCC outcome. The length of survival of the patients with high EphA2 expression was shorter than that of the patients with a low level of expression (relative risk, 2.304; 95% CI, 1.102–4.818; P=0.027). The analysis of the expression levels of EphA2 in tumor tissues may aid in the identification of the patient subgroup that are at a high risk of a poor disease outcome.

Predictive chromosomal clusters of synchronous and metachronous brain metastases in clear cell renal cell carcinoma

Synchronous (early) and metachronous (late) brain metastasis (BM) events of sporadic clear cell renal cell carcinoma (ccRCC) (n = 148) were retrospectively analyzed using comparative genomic hybridization (CGH). Using oncogenetic tree models and cluster analyses, chromosomal imbalances related to recurrence-free survival until BM (RFS-BM) were analyzed. Losses at 9p and 9q appeared to be hallmarks of metachronous BM events, whereas an absence of detectable chromosomal changes at 3p was often associated with synchronous BM events. Correspondingly, k-means clustering showed that cluster 1 cases generally exhibited low copy number chromosomal changes that did not involve 3p. Cluster 2 cases had a high occurrence of -9p/-9q (94-98%) deletions, whereas cluster 3 cases had a higher frequency of copy number changes, including loss at chromosome 14 (80%). The higher number of synchronous cases in cluster 1 was also associated with a significantly shorter RFS-BM compared with clusters 2 and 3 (P = 0.02). Conversely, a significantly longer RFS-BM was observed for cluster 2 versus clusters 1 and 3 (P = 0.02). Taken together, these data suggest that metachronous BM events of ccRCC are characterized by loss of chromosome 9, whereas synchronous BM events may form independently of detectable genetic changes at chromosomes 9 and 3p.

Single nucleotide polymorphisms in the mitochondrial displacement loop and age-at-onset of renal cell carcinoma

The accumulation of single nucleotide polymorphisms (SNPs) in the displacement loop (D-loop) of mitochondrial DNA (mtDNA) has been described in various types of cancers, and their association with cancer risk and disease outcome has been extensively identified. In the present study, we investigated the association between age-at-onset and SNPs in the mitochondrial D-loop using a population-based series of renal cell carcinoma(RCC). The SNP sites of nucleotides 16293A/G were identified for their association with age-at-onset using the log-rank test. The age-at-onset of patients with the minor allele G genotype was significantly lower than that of patients with the A genotype at the 16293 site (p < 0.001). Genetic polymorphisms in the D-loop are predictive markers of age-at-onset in RCC patients. Accordingly, the analysis of genetic polymorphisms in the mitochondrial D-loop may help identify RCC patient subgroups at high risk of early onset.

A phase II trial of sunitinib in patients with renal cell cancer and untreated brain metastases

BACKGROUND

The expanded access program and anecdotal cases suggested sunitinib is safe in RCC patients with BM and might have worthwhile activity.

PATIENTS AND METHODS

In a phase II trial, patients with untreated BM received the standard regimen of sunitinib. The primary end point was objective response (OR) rate in BM after 2 cycles. An OR rate of 35% was prospectively defined as the minimum needed to warrant further investigation. According to Simon's optimal 2-stage design, at least 3 of the initial 15 patients had to have an OR for accrual to continue.

RESULTS

Among 16 evaluable patients, 1 had a complete response outside the central nervous system (CNS). CNS disease was stabilized in 5 (31%). However, no BM showed an OR. Therefore, no further accrual took place. Median time to progression was 2.3 months and overall survival was 6.3 months. There was 1 toxic death, from peritonitis with gastric perforation. Three patients experienced at least 1 treatment-related grade 3 or greater toxicity but no neurological adverse events were attributable to sunitinib.

CONCLUSION

Although tolerability was acceptable in RCC patients with previously untreated BM, sunitinib has limited efficacy in this setting.

Single nucleotide polymorphisms in the D-loop region of mitochondrial DNA is associated with renal cell carcinoma outcome

Accumulation of single nucleotide polymorphisms (SNPs) in the displacement loop (D-loop) of mitochondrial DNA (mtDNA) has been described in various types of cancers and might be associated with cancer risk and disease outcome. We identified 14 SNPs with a frequency higher than 5% and 5 SNPs associated with the risk of renal cell carcinoma (RCC) in a case-control study previously. In the present study, we assessed the relationship of these SNPs and the outcome of RCC patients, a SNP of 262C/T was identified by the log-rank test for statistically significant prediction of RCC survival. In an overall multivariate analysis, allele 262 was identified as an independent predictor of RCC outcome. The length of survival of patients with 262T was significantly shorter than that of patients with allele 262C (relative risk, 2.136, 95%CI, 1.863-2.449; p = 0.000). The analysis of genetic polymorphisms in the mitochondrial D-loop can help identify patients subgroup at high risk of a poor disease outcome.

Identification of sequence polymorphisms in the displacement loop region of mitochondrial DNA as a risk factor for renal cell carcinoma

The accumulation of single-nucleotide polymorphisms (SNPs) in the displacement loop (D-loop) of mitochondrial DNA (mtDNA) may be associated with an increased cancer risk. In this case-control study, the SNPs in the mitochondrial D-loop of renal cell carcinoma (RCC) patients were identified and their association with cancer risk was evaluated. The minor alleles of nucleotides 16293A/G, 262A/G and 488T/C were associated with an increased risk, whereas the minor alleles of nucleotides 16298T/C and 16319G/A were associated with a decreased risk for RCC. Moreover, the nucleotides 16293, 262, 16298 and 16319 were identified as specifically associated with the risk of clear cell RCC (ccRCC), whereas 262 and 488 were specifically associated with papillary RCC and renal oncocytoma. In conclusion, SNPs in mtDNA are potential modifiers of RCC. The analysis of genetic polymorphisms in the mitochondrial D-loop may help identify the patient subgroups at a high risk of developing RCC.

Novel agents in renal carcinoma: a reality check

The discovery of the molecular mechanisms underlying development of renal cell carcinoma have allowed for the development of novel targeted therapy for treatment of this disease. Recently, multiple agents have become approved by regulatory authorities for the treatment of advanced renal cell carcinoma, including sunitinib, sorafenib, bevacizumab (with interferon alpha), pazopanib, temsirolimus and everolimus. While these therapies have generated excitement and have clearly altered the treatment paradigm, multiple limitations have been elucidated over time. These include but are not limited to the fact that treatment is not associated with complete responses, a significant number of patients are primarily refractory to treatment, and clinical trials mostly include clear cell histology. Furthermore, the role of these therapies in the treatment of brain metastases remains unclear and therapies can have considerable toxicities. RECIST criteria (Response Evaluation Criteria In Solid Tumors) can be inadequate for the assessment of these modalities' treatment efficacy, and biomarkers predictive of individual patient benefit have been elusive. This review summarizes the major clinical data and discusses these limitations.

Role of radiation therapy in the management of renal cell cancer

Renal cell carcinoma (RCC) is traditionally considered to be radioresistant; therefore, conventional radiotherapy (RT) fraction sizes of 1.8 to 2 Gy are thought to have little role in the management of primary RCC, especially for curative disease. In the setting of metastatic RCC, conventionally fractionated RT has been an effective palliative treatment in 50% of patients. Recent technological advances in radiation oncology have led to the clinical implementation of image-guided radiotherapy, allowing biologically potent doses to the tumors intra- and extra-cranially. As predicted by radiobiologic modeling, favorable outcomes have been observed with highly hypofractionated schemes modeled after the experience with intracranial stereotactic radiosurgery (SRS) for RCC brain metastases with reported local control rates averaging 85%. At present, both primary and metastatic RCC tumors may be successfully treated using stereotactic approaches, which utilize steep dose gradients to maximally preserve function and avoid toxicity of adjacent organs including liver, uninvolved kidney, bowel, and spinal cord regions. Future endeavors will combine stereotactic body radiation therapy (SBRT) with novel targeted therapies, such as tyrosine kinase inhibitors and targeted rapamycin (mTOR) inhibitors, to maximize both local and systemic control.