Metastatic non-clear cell renal cell carcinoma: an evidence based review of current treatment strategies

Different outcomes among patients with intermediate-risk metastastic renal cell carcinoma treated with first-line tyrosine-kinase inhibitors

INTRODUCTION

Systemic therapy of patients with metastatic renal cell carcinoma (mRCC) has improved in the past years, with the advent of new immunotherapy-based combinations as a standard treatment option for first-line therapy. Nevertheless, particularly in good-risk patients by IMDC criteria, tyrosine-kinase inhibitors (TKI) may remain as an option for some patients. We reviewed our experience with TKI as first-line therapy for mRCC patients, trying to identify subgroups of patients that may still benefit from this strategy.

MATERIAL AND METHODS

All patients with mRCC treated with first-line TKI, and adequate follow-up, in University Hospital La Paz (Madrid, Spain) between 2007 and 2020 were analyzed. Patients treated inside a clinical trial were excluded from this analysis.

RESULTS

A total of 90 patients treated with first-line TKI were included. Regarding IMDC criteria, 33 patients (36.7%) were good-risk, 41 patients (45.5%) intermediate-risk, and 16 patients (17.8%) poor-risk. With a median follow-up of 49 months, the median overall survival (OS) for good, intermediate, and poor-risk patients was 54, 24, and 16 months (p = 0.004). When intermediate-risk was divided into patients with 1 or 2 risk factors, differences in OS were also statistically significant: patients with 1 risk factor had a median OS of 33 months, while patients with 2 risk factors had a median OS of 16 months, the same as poor-risk patients (p = 0.003). In the multivariate analysis, trying to find out which of the IMDC factors had a more remarkable weight in the prognosis of the patients, both ECOG and hemoglobin levels by themselves were significantly associated with OS.

CONCLUSION

In our group of patients, survival outcomes were different among patients with intermediate-risk with 1 or 2 risk factors by IMDC criteria. These could help select patients that may benefit from first-line treatment with a TKI, particularly in settings with difficult access to novel therapies, such as immunotherapy-based combinations.

Near-Infrared Photoimmunotherapy (NIR-PIT) in Urologic Cancers

Near-infrared photoimmunotherapy (NIR-PIT) is a novel molecularly-targeted therapy that selectively kills cancer cells by systemically injecting an antibody-photoabsorber conjugate (APC) that binds to cancer cells, followed by the application of NIR light that drives photochemical transformations of the APC. APCs are synthesized by selecting a monoclonal antibody that binds to a receptor on a cancer cell and conjugating it to IRDye700DX silica-phthalocyanine dye. Approximately 24 h after APC administration, NIR light is delivered to the tumor, resulting in nearly-immediate necrotic cell death of cancer cells while causing no harm to normal tissues. In addition, NIR-PIT induces a strong immunologic effect, activating anti-cancer immunity that can be further boosted when combined with either immune checkpoint inhibitors or immune suppressive cell-targeted (e.g., regulatory T cells) NIR-PIT. Currently, a global phase III study of NIR-PIT in recurrent head and neck squamous cell carcinoma is ongoing. The first APC and NIR laser systems were approved for clinical use in September 2020 in Japan. In the near future, the clinical applications of NIR-PIT will expand to other cancers, including urologic cancers. In this review, we provide an overview of NIR-PIT and its possible applications in urologic cancers.

Epigenetic inactivation of ACAT1 promotes epithelial-mesenchymal transition of clear cell renal cell carcinoma

BACKGROUND

Acetyl-CoA acyltransferase 1 (ACAT1) is a key enzyme catalyzing the production of mitochondrial ketone bodies. We have shown that ACAT1 is down-regulated in kidney renal clear cell carcinoma (KIRC) previously.

OBJECTIVE

To investigate the reasons for downregulation of ACAT1 in KIRC and explore the underlying mechanisms involved in metastatic inhibition regulated by ACAT1.

METHODS

The Gene Expression Omnibus (GEO) database was queried for meta-analysis of ACAT1 mRNA expression in KIRC. The UALCAN website was used to compare the methylation levels of the ACAT1 promoter region in KIRC and normal tissues. RT-qPCR was used to quantitate ACAT1 transcription levels. The GCBI and Tarbase V.8 databases were used to predict miRNAs that may target the mRNA of ACAT1. The correlation between mRNA expression of ACAT1, MMP7 (matrix metallopeptidase 7), CDH1 (E-cadherin), EpCAM (epithelial cell adhesion molecule), and VIM (vimentin) was analyzed. Extracellular MMP7 protein was quantitated using an ELISA assay.

RESULTS

The methylation level of the ACAT1 promoter region in KIRC was significantly higher than that in the normal kidney tissues. The ACAT1 mRNA expression in the KIRC cell lines was restored after treatment with 5-aza-dC (p < 0.05). MiR-21-5p is a conserved microRNA targeting ACAT1. It is expressed at a significantly higher level in KIRC than in normal tissues (p < 0.001). MiR-21-5p miRNA expression negatively correlates with ACAT1 mRNA expression. The expression of miR-21-5p is higher at the T3-T4 stages and in the histologic grades G3-G4. Patients with high miR-21-5p expression tended to have lower overall survival, suggesting that miR-21-5p could serve as a potentially valuable diagnostic biomarker for KIRC (AUC = 0.957; p < 0.001). A mimetic of miR-21-5p inhibited the expression of ACAT1 mRNA and protein. In addition, ACAT1 mRNA expression positively correlates with CDH1 and EpCAM but is negatively correlated with VIM. Overexpression of ACAT1 suppresses the secretion of MMP7 in KIRC cells.

CONCLUSION

Expression of ACAT1 in KIRC is controlled at two levels, firstly by the hypermethylation of the ACAT1 promoter region and secondly by overexpression of miR-21-5p. Downregulation of ACAT1 expression correlates with epithelial-mesenchymal transition (EMT).

Quaking I-5 protein inhibits invasion and migration of kidney renal clear cell carcinoma via inhibiting epithelial-mesenchymal transition suppression through the regulation of microRNA 200c

Background

It has been demonstrated that quaking I-5 protein (QKI-5) plays crucial roles in the metastasis of various kinds of cancers. However, the function and mechanism of QKI-5 in kidney renal clear cell carcinoma (KIRC) metastasis remains unclear. Therefore, this study aimed to explore the mechanism of QKI-5 in the metastasis of KIRC.

Methods

The expression of QKI-5 was detected using real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot in KIRC tissues and different cell lines. Immunohistochemical staining was used to detect the quantity of QKI-5 in primary and metastases of KIRC. Cell migration and invasion were measured using wound healing and transwell assays respectively. The quantity of epithelial mesenchymal transition marker proteins was detected using western blot and immunofluorescence staining. The interaction of QKI-5 via microRNA 200c (miR-200c) was confirmed using dual luciferase reporter assay.

Results

Although QKI-5 was significantly more likely to be downregulated in KIRC tissues than that in normal Kidney tissues, it was dramatically elevated in metastatic KIRC tumors. Upregulation of QKI-5 promoted cell migration and invasion and elevated the expression of epithelial-mesenchymal transition (EMT) marker proteins, including vimentin, snail and slug, while it was downregulated for E-cadherin. Furthermore, a dual luciferase reporter assay demonstrated that QKI-5 was a direct target of miR-200c, and that miR-200c could reverse the effect of QKI-5 on cell migration, invasion, and expression of EMT marker proteins.

Conclusions

Our results revealed that downregulation of QKI-5 by miR-200c attenuated KIRC migration and invasion via the EMT process, indicating that QKI-5 may be a potential therapeutic target and a key indicator of KIRC progression.

Treatment outcomes of metastatic nonclear cell renal cell carcinoma: A single institution retrospective analysis

Introduction:

Nonclear cell (NCC) metastatic renal cell carcinoma (mRCC) is a biologically heterogeneous entity. We report the outcomes of NCC mRCC treated with first-line vascular endothelial growth factor (VEGF) inhibitors or mammalian target of rapamycin (mTOR) inhibitors at our institute. This is first such report from India.

Methods:

This is a retrospective analysis of the 40 consecutive patients of NCC mRCC treated between January 2013 and June 2015 in routine clinical practice at our institute. The primary endpoint analyzed was overall survival (OS) with respect to the type of first-line treatment and tumor histology.

Results:

The most common histological subtype was papillary in 25 patients (62.5%) followed by sarcomatoid in six (15%), chromophobe in 5 (12.5%), translocation-associated in one patient, and other nonspecified in three patients. First-line treatment was sorafenib in 14 (35%), sunitinib in 9 (22.5%), pazopanib in 8 (20%), everolimus in seven (17.5%), and best-supportive care (BSC) in two (5%) patients. Partial response, stable disease, and progression was observed in six (15%), 13 (32.5%), and nine (22.5%) cases, respectively, as the best response to first-line treatment. The median OS was 11.7 months and median event-free survival was 6.1 months in the whole cohort. The median OS in months for different first-line treatments were as follows: sorafenib (16.2), sunitinib (11.7), pazopanib (not reached, mean-23.9 ± 6.0), everolimus (4.1) and BSC (0.6) and for different histological subtypes were as follows: papillary (9.8), chromophobe (not reached, mean-30.3 ± 8.4), sarcomatoid (4.1), and others (7.9).

Conclusions:

Chromophobe histology has a better outcome compared to other histological subtypes, and anti-VEGF tyrosine kinase inhibitors are preferable first-line agents compared to mTOR inhibitors.

Prevalence of Germline Mutations in Cancer Susceptibility Genes in Patients With Advanced Renal Cell Carcinoma

Importance

Identification of patients with hereditary renal cell carcinoma (RCC) is important for cancer screening and, in patients with advanced disease, for guiding treatment. The prevalence of cancer-related germline mutations in patients with advanced RCC and the phenotypes associated with some rare mutations are unknown.

Objectives

To examine the prevalence of germline mutations in both known RCC predisposition genes and other cancer-associated genes and to identify clinical and pathologic factors associated with germline mutations.

Design, Setting, and Participants

In this cohort study conducted from October 1, 2015, to July 31, 2017, 254 of 267 patients with advanced (American Joint Committee on Cancer stage III or IV) RCC who were seen in medical oncology or urology clinics agreed to germline sequencing and disclosure of results under an institutional protocol of matched tumor-germline DNA sequencing.

Main Outcomes and Measures

Mutation prevalence and spectrum in patients with advanced RCC were determined. Clinical characteristics were assessed by mutation status.

Results

Of the 254 patients (median age [range], 56 [13-79] years; 179 [70.5%] male; 211 [83.1%] non-Hispanic white), germline mutations were identified in 41 (16.1%); 14 (5.5%) had mutations in syndromic RCC-associated genes (7 in FH, 3 in BAP1, and 1 each in VHL, MET, SDHA, and SDHB). The most frequent mutations were CHEK2 (n = 9) and FH (n = 7). Of genes not previously associated with RCC risk, CHEK2 was overrepresented in patients compared with the general population, with an odds ratio of RCC of 3.0 (95% CI, 1.3-5.8; P = .003). Patients with non-clear cell RCC were significantly more likely to have an RCC-associated gene mutation (9 [11.7%] of 74 vs 3 [1.7%] of 177; P = .001), and 8 (10.0%) had a mutation in a gene that could guide therapy. Of patients with mutations in RCC-associated genes, 5 (35.7%) failed to meet current clinical guidelines for genetic testing.

Conclusions and Relevance

Of patients with non-clear cell RCC, more than 20% had a germline mutation, of which half had the potential to direct systemic therapy. Current referral criteria for genetic testing did not identify a substantial portion of patients with mutations, supporting the role of a more inclusive sequencing approach.

Comprehensive Genomic Analysis of Metastatic Non-Clear-Cell Renal Cell Carcinoma to Identify Therapeutic Targets

PURPOSE

Non-clear-cell renal cell carcinoma (nccRCC) encompasses approximately 20% of renal cell carcinomas and includes subtypes that vary in clinical and molecular biology. Compared with clear cell renal cell carcinoma, nccRCC demonstrates limited sensitivity to conventional vascular endothelial growth factor- and mammalian target of rapamycin-directed agents, indicating a need for better therapies. Characterizing the genomic landscape of metastatic nccRCC variants may help define novel therapeutic strategies.

PATIENTS AND METHODS

We retrospectively analyzed tumor tissue from patients with metastatic nccRCC who consented to genomic analysis of their tumor and germline DNA. A hybridization capture-based assay was used to identify single nucleotide variants and small insertions and deletions across more than 340 cancer-associated genes with germline comparison. Clinical actionability of somatic mutations was assessed using OncoKB levels of evidence. Microsatellite instability (MSI) in the tumor was investigated.

RESULTS

Of 116 patients included in the analysis, 57 (49%) presented with de novo metastatic disease, and 59 (51%) presented with localized disease that later metastasized. Subtype classifications included unclassified (n = 41; 35%), papillary (n = 26; 22%), chromophobe (n = 17; 15%), translocation associated (n = 13; 11%), and other (n = 19; 16%). Of all tumors, 15 (13%) had putative driver somatic alterations amenable to targeted therapies, including alterations in MET, TSC1/2, and an ALK translocation. Of 45 patients who had germline testing, 11 (24%) harbored mutations, seven of which could potentially guide therapy. Of 115 available tumors for analysis, two (1.7%) had high and six (5%) had intermediate MSI status.

CONCLUSION

The mutation profiles of metastatic nccRCC vary by subtype. Comprehensive analysis of somatic mutations, germline mutations, and MSI, interpreted via an annotated precision oncology knowledge base, identified potentially targetable alterations in 22% of patients, which merits additional investigation.

Nobiletin inhibits hypoxia-induced epithelial-mesenchymal transition in renal cell carcinoma cells

Hypoxia is a universal characteristic of solid tumor and involving cancer metastasis via epithelial-mesenchymal transition (EMT). Nobiletin (3',4',5,6,7,8-hexamethoxyflavone), a dietary polymethoxylated flavonoid found in citrus fruits, has been reported to have anticancer effects. However, the possible role of nobiletin in renal cell carcinoma (RCC) remains unclear. Thus, the aim of this study was to identify the effect of nobiletin on hypoxia-induced EMT in RCC cells. We found that nobiletin significantly inhibited the migration and invasion induced by hypoxia in RCC cells. In addition, nobiletin reversed the hypoxia-induced EMT process in RCC cells. Furthermore, nobiletin suppressed the activation of NF-κB and Wnt/β-catenin signaling pathways in hypoxia-stimulated RCC cells. In conclusion, these findings demonstrate that nobiletin inhibits hypoxia-induced EMT in human RCC cells via the inactivation of the NF-κB and Wnt/β-catenin signaling pathways.

Sources of Frustration Among Patients Diagnosed With Renal Cell Carcinoma

Despite numerous therapeutic advances in renal cell carcinoma (RCC), little is known about patients' perspectives on cancer care. An international survey was conducted to identify points of frustration associated with cancer care reported by patients with RCC. Data were obtained from an online survey, conducted from April 1 to June 15, 2017, through social media and patient networking platforms. This survey obtained baseline demographic, clinicopathologic, and treatment-related information. Open-ended questions accessed sources of frustration in cancer-related care and patients' suggestions for amelioration. Responses were categorized and reviewed by independent reviewers. A qualitative analysis was performed and the Kruskal-Wallis test was used to define associations between baseline characteristics and sources of frustration. Among 450 patients surveyed, 71.5% reported sources of frustration, classified as either emotional (48.4%) or practical (23.1%). The most common were fear of recurrence/progression (15.8%), distrust of their cancer care system (12.9%), and lack of appropriate information (9.8%). Female gender and non-clear cell histology were associated with both types of frustration, and older age was linked to practical sources of frustration. Patients suggested solutions included greater compassion among health care practitioners (20.7%), better access to information (15.1%) and research to improve their chances of being cured (14.7%). Sources of frustration related to emotional and practical causes were identified amongst patients with RCC. Certain demographic and clinical characteristics were associated with more sources of frustration. This study provides the first characterization of specific ways to improve the patient experience by addressing common frustrations.

Pazopanib for the Treatment of Non-clear Cell Renal Cell Carcinoma: A Single-Arm, Open-Label, Multicenter, Phase II Study

PURPOSE

The optimal treatment strategy for patients with metastatic non-clear cell type renal cell carcinoma (nccRCC) remains unclear. Although several inhibitors of vascular endothelial growth factor have recently shown efficacy against nccRCC, the clinical benefit of pazopanib in nccRCC has not been analyzed. We therefore designed a single-arm, open-label, phase II study to determine the efficacy and safety of pazopanib in patients with nccRCC.

MATERIALS AND METHODS

Patientswith locally advanced or metastatic nccRCC, exceptfor collecting duct or sarcomatoid type, received 800 mg/day of pazopanib daily until progression of disease or intolerable toxicity. One cyclewas defined as 4weeks and tumorresponsewas evaluated every two cycles. The primary objective was overall response rate (ORR).

RESULTS

A total of 29 eligible patients were enrolled at nine centers in Korea from December 2012 and September 2014. The median age of the patients was 58 years (range, 27 to 76 years) and 21 patients (72%) were male. Regarding histology type, 19 patients had papillary, three had chromophobe, two had unclassified and five had unknown non-clear cell type. Of 28 evaluable patients, eight achieved a confirmed partial response with ORR of 28%. The median progression-free survival was 16.5 months (95% confidence interval, 10.9 to 22.1) and median overall survival was not reached. Sixteen patients (55%) experienced treatment-related toxicity of grade 3 or more, but most adverse events were overcome through dose reduction and delay.

CONCLUSION

In this prospective phase II study, pazopanib demonstrated promising activity and tolerable safety profile in patients with metastatic nccRCC.

Involvement of erbB4 and tumor marker genes in renal carcinoma regulatory network

Background

Renal carcinoma is a common urologic tumor, and there is no ideal tumor marker for clinical diagnosis except for imaging diagnosis. This study aims to screen the serum tumor markers closely related with the benign and malignant of renal carcinoma out and chart out the regulatory network that involves renal carcinoma-related genes.

Methods

Based on 96 pathologically diagnosed renal cancer patients, factors strongly linked to renal carcinoma character were selected using Fisher discriminant analysis. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases were utilized to manipulate function annotation of erbB4 and the selected genes and pathway analysis.

Results

Four essential tumor markers CYFRA21-1, CA125, VHL and HIF-1β were successfully screened out. Using GO and KEGG databases, the regulatory network of renal cancer cell escaping apoptosis was charted out on the basis of erbB4 signaling pathway.

Conclusion

Serum tumor marker genes play a certain part in the genesis and development of renal carcinoma. We preliminarily illustrated the molecular mechanism of these markers to predict tumor, laying a foundation for further exploration in renal carcinoma.

Genomic classifications of renal cell carcinoma: a critical step towards the future application of personalized kidney cancer care with pan-omics precision

Over the past 20 years, classifications of kidney cancer have undergone major revisions based on morphological refinements and molecular characterizations. The 2016 WHO classification of renal tumors recognizes more than ten different renal cell carcinoma (RCC) subtypes. Furthermore, the marked inter- and intra-tumor heterogeneity of RCC is now well appreciated. Nevertheless, contemporary multi-omics studies of RCC, encompassing genomics, transcriptomics, proteomics, and metabolomics, not only highlight apparent diversity but also showcase and underline commonality. Here, we wish to provide an integrated perspective concerning the future 'functional' classification of renal cancer by bridging gaps among morphology, biology, multi-omics, and therapeutics. This review focuses on recent progress and elaborates the potential value of contemporary pan-omics approaches with a special emphasis on cancer genomics unveiled through next-generation sequencing technology, and how an integrated multi-omics approach might impact precision-based personalized kidney cancer care in the near future. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Tumor Xenografts of Human Clear Cell Renal Cell Carcinoma But Not Corresponding Cell Lines Recapitulate Clinical Response to Sunitinib: Feasibility of Using Biopsy Samples

BACKGROUND

Parallel development of preclinical models that recapitulate treatment response observed in patients is central to the advancement of personalized medicine.

OBJECTIVE

To evaluate the use of biopsy specimens to develop patient-derived xenografts and the use of corresponding cell lines from renal cell carcinoma (RCC) tumors for the assessment of histopathology, genomics, and treatment response.

DESIGN, SETTING, AND PARTICIPANTS

A total of 74 tumor specimens from 66 patients with RCC were implanted into immunocompromised NOD-SCID IL2Rg-/- mice. Four cell lines generated from patients' specimens with clear cell pathology were used for comparative studies.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Preclinical models were established and assessed. Engraftment rates were analyzed using chi-square testing. Analysis of variance (two-way analysis of variance) was conducted to assess tumor growth.

RESULTS AND LIMITATIONS

Overall, 33 RCC mouse xenograft models were generated with an overall engraftment rate of 45% (33 of 74). Tumor biopsies engrafted comparably with surgically resected tumors (58% vs 41%; p=0.3). Xenograft tumors and their original tumors showed high fidelity in regard to histology, mutation status, copy number change, and targeted therapy response. Engraftment rates from metastatic tumors were higher but not more significant than primary tumors (54% vs 34%; p=0.091). Our engraftment rate using metastases or biopsies was comparable with recent reports using resected primary tumors. In stark contrast to corresponding cell lines, all tested xenografts recapitulated patients' clinical response to sunitinib.

CONCLUSIONS

Patient-derived xenograft models can be effectively established from tumor biopsies. Preclinical xenograft models but not matched cell lines reflected clinical responses to sunitinib.

PATIENT SUMMARY

Matched patient-derived clear cell renal cell carcinoma xenografts and cell lines from responsive and refractory patients treated with sunitinib were established and evaluated for pharmacologic response to anti-vascular endothelial growth factor treatment. Both models accurately reflected the genetic characteristics of original tumors, but only xenografts recapitulated drug responses observed in patients. These models could serve as a powerful platform for precision medicine.

Comparative Genomic Profiling of Matched Primary and Metastatic Tumors in Renal Cell Carcinoma

BACKGROUND

Next-generation sequencing (NGS) studies of matched pairs of primary and metastatic tumors in renal cell carcinoma (RCC) have been limited to small cohorts.

OBJECTIVE

To evaluate the discordance in somatic mutations between matched primary and metastatic RCC tumors.

DESIGN, SETTING, AND PARTICIPANTS

Primary tumor (P), metastasis (M), and germline DNA from 60 patients with RCC was subjected to NGS with a targeted exon capture-based assay of 341 cancer-associated genes. Somatic mutations were called using a validated pipeline.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Mutations were classified as shared (S) or private (Pr) in relation to each other within individual P-M pairs. The concordance score was calculated as (S-Pr)/(S+Pr). To calculate enrichment of Pr/S mutations for a particular gene, we calculated a two-sided p value from a binomial model for each gene with at least ten somatic mutation events, and also implemented a separate permutation test procedure. We adjusted p values for multiple hypothesis testing using the Benjamini-Hochberg procedure. The mutation discordance was calculated using Mann-Whitney U tests according to gene mutations or metastatic sites.

RESULTS AND LIMITATIONS

Twenty-one pairs (35%) showed Pr mutations in both P and M samples. Of the remaining 39 pairs (65%), 14 (23%) had Pr mutations specific to P samples, 12 (20%) had Pr mutations to M samples, and 13 (22%) had identical somatic mutations. No individual gene mutation was preferentially enriched in either P or M samples. P-M pairs with SETD2 mutations demonstrated higher discordance than pairs with wild-type SETD2. We observed that patients who received therapy before sampling of the P or M tissue had higher concordance of mutations for P-M pairs than patients who did not (Mann-Whitney p=0.088).

CONCLUSIONS

Our data show mutation discordance within matched P-M RCC tumor pairs. As most contemporary precision medicine trials do not differentiate mutations detected in P and M tumors, the prognostic and predictive value of mutations in P versus M tumors warrants further investigation.

PATIENT SUMMARY

In this study we evaluated the concordance of mutations between matched primary and metastatic tumors for 60 kidney cancer patients using a panel of 341 cancer genes. Forty-seven patients carried nonidentical cancer gene mutations within their matched primary-metastatic pair. The mutation profile of the primary tumor alone could compromise precision in selecting effective targeted therapies and result in suboptimal clinical outcomes.

Genomic landscape and evolution of metastatic chromophobe renal cell carcinoma

Chromophobe renal cell carcinoma (chRCC) typically shows ~7 chromosome losses (1, 2, 6, 10, 13, 17, and 21) and ~31 exonic somatic mutations, yet carries ~5%-10% metastatic incidence. Since extensive chromosomal losses can generate proteotoxic stress and compromise cellular proliferation, it is intriguing how chRCC, a tumor with extensive chromosome losses and a low number of somatic mutations, can develop lethal metastases. Genomic features distinguishing metastatic from nonmetastatic chRCC are unknown. An integrated approach, including whole-genome sequencing (WGS), targeted ultradeep cancer gene sequencing, and chromosome analyses (FACETS, OncoScan, and FISH), was performed on 79 chRCC patients including 38 metastatic (M-chRCC) cases. We demonstrate that TP53 mutations (58%), PTEN mutations (24%), and imbalanced chromosome duplication (ICD, duplication of ≥ 3 chromosomes) (25%) were enriched in M-chRCC. Reconstruction of the subclonal composition of paired primary-metastatic chRCC tumors supports the role of TP53, PTEN, and ICD in metastatic evolution. Finally, the presence of these 3 genomic features in primary tumors of both The Cancer Genome Atlas kidney chromophobe (KICH) (n = 64) and M-chRCC (n = 35) cohorts was associated with worse survival. In summary, our study provides genomic insights into the metastatic progression of chRCC and identifies TP53 mutations, PTEN mutations, and ICD as high-risk features.

Persistent Severe Hyperlactatemia and Metabolic Derangement in Lethal SDHB-Mutated Metastatic Kidney Cancer: Clinical Challenges and Examples of Extreme Warburg Effect

To describe the unique clinical features, determine the genomics, and investigate the metabolic derangement of an extremely rare form of a hereditary lethal kidney cancer syndrome.

Patients and Methods

Three patients with lethal kidney cancer (age 19, 20, and 37 years) exhibiting persistent (1 to 3 months) extremely high levels of blood lactate (> 5 mM) despite normal oxygen perfusion, highly avid tumors on [18F]fluorodeoxyglucose positron emission tomography (PET), and pleomorphic histopathologic features were identified and treated in a single institute. Integrated studies including whole-genome sequencing (WGS), targeted sequencing, immunohistochemistry, cell-based assays, and 18F-glutamine PET imaging were performed to investigate this rare kidney cancer syndrome.

Results

All three patients with kidney cancer were initially given various diagnoses as a result of diverse tumor histopathology and atypical clinical presentations. The correct diagnoses of these SDHB-mutated renal cell carcinomas were first made based on cancer genomics. Genomic studies of the blood and tumors of these patients identified three different kinds of germline loss-of-function mutations in the SDHB gene and the common loss of heterozygosity in the remaining SDHB allele thorough somatic chromosome 1p deletion. In one patient, WGS revealed that a germline mutation of SDHB coupled with loss of heterozygosity was the sole genetic event. Cancer evolution analysis of SDHB tumors based on WGS demonstrated that SDHB in kidney epithelium fulfills the Knudson two-hit criteria as a major tumor suppressor gene. SDHB -/- tumor cells displayed increase in glucose uptake and lactate production, alteration in mitochondrial architecture, and defect in oxidative respiration. 18F-Glutamine PET imaging studies demonstrated increased glutamine metabolism.

Conclusion

SDHB-deficient metastatic renal cell carcinoma is a rare, aggressive form of kidney cancer that manifests with clinical evidence of a severe Warburg effect, and genomic studies demonstrated two genetic hits at SDHB genes during kidney tumorigenesis.

Assessment of ethnic differences in sunitinib outcome between Caucasian and Asian patients with metastatic renal cell carcinoma: a meta-analysis

BACKGROUND

An increasing number of studies have reported ethnic differences in sunitinib outcome in metastatic renal cell carcinoma (mRCC) patients. However, a comprehensive analysis is still lacking. Therefore, we systematically collected available published data and performed a meta-analysis to compare sunitinib efficacy and toxicity in Asian and Caucasian mRCC patients.

METHODS

Data were extracted from published results from clinical trials, expanded access program and real-world clinical practice. Progression-free survival (or time to tumor progression), overall survival, objective response rate and adverse events were used as endpoints to evaluate the differences of sunitinib outcome between the two ethnicities. For adverse events, we focused the following clinically relevant side effects: diarrhea, fatigue, mucositis/stomatitis, hand-foot syndrome, hypertension, leukopenia, neutropenia and thrombocytopenia.

RESULTS

A total of 33 publications including 9977 patients were available for meta-analysis. The efficacy of sunitinib in Asian patients was similar to that in Caucasian patients. However, Asian patients showed a higher incidence of all grades toxicity of hand-foot syndrome, > grade 2 fatigue, > grade 2 hand-foot syndrome and > grade 2 thrombocytopenia.

CONCLUSION

Ethnic differences in adverse events of sunitinib in mRCC patients existed and dose adjustment in Asian patients may be considered.

Overcome tumor heterogeneity-imposed therapeutic barriers through convergent genomic biomarker discovery: A braided cancer river model of kidney cancer

Tumor heterogeneity, encompassing genetic, epigenetic, and microenvironmental variables, is extremely complex and presents challenges to cancer diagnosis and therapy. Genomic efforts on genetic intratumor heterogeneity (G-ITH) confirm branched evolution, support the trunk-branch cancer model, and present a seemingly insurmountable obstacle to conquering cancers. G-ITH is conspicuous in clear cell renal cell carcinoma (ccRCC), where its presence complicates identification and validation of biomarkers and thwarts efforts in advancing precision cancer therapeutics. However, long-term clinical benefits on targeted therapy are not uncommon in metastatic ccRCC patients, implicating that there are underlying constraints during ccRCC evolution, which in turn force a nonrandom sequence of parallel gene/pathway/function/phenotype convergence within individual tumors. Accordingly, we proposed a "braided cancer river model" depicting ccRCC evolution, which deduces cancer development based on multiregion tumor genomics of exceptional mTOR inhibitor (mTORi) responders. Furthermore, we employ an outlier case to explore the river model and highlight the importance of "Five NGS Matters: Number, Frequency, Position, Site and Time" in assessing cancer genomics for precision medicine. This mutable cancer river model may capture clinically significant phenotype-convergent events, predict vulnerability/resistance mechanisms, and guide effective therapeutic strategies. Our model originates from studying exceptional responders in ccRCC, which warrants further refinement and future validation concerning its applicability to other cancer types. The goal of this review is employing kidney cancer as an example to illustrate critical issues concerning tumor heterogeneity.

Renal cell carcinoma

Renal cell carcinoma (RCC) denotes cancer originated from the renal epithelium and accounts for >90% of cancers in the kidney. The disease encompasses >10 histological and molecular subtypes, of which clear cell RCC (ccRCC) is most common and accounts for most cancer-related deaths. Although somatic VHL mutations have been described for some time, more-recent cancer genomic studies have identified mutations in epigenetic regulatory genes and demonstrated marked intra-tumour heterogeneity, which could have prognostic, predictive and therapeutic relevance. Localized RCC can be successfully managed with surgery, whereas metastatic RCC is refractory to conventional chemotherapy. However, over the past decade, marked advances in the treatment of metastatic RCC have been made, with targeted agents including sorafenib, sunitinib, bevacizumab, pazopanib and axitinib, which inhibit vascular endothelial growth factor (VEGF) and its receptor (VEGFR), and everolimus and temsirolimus, which inhibit mechanistic target of rapamycin complex 1 (mTORC1), being approved. Since 2015, agents with additional targets aside from VEGFR have been approved, such as cabozantinib and lenvatinib; immunotherapies, such as nivolumab, have also been added to the armamentarium for metastatic RCC. Here, we provide an overview of the biology of RCC, with a focus on ccRCC, as well as updates to complement the current clinical guidelines and an outline of potential future directions for RCC research and therapy.

Genomic differences between black and white patients implicate a distinct immune response to papillary renal cell carcinoma

Significant disparities in survival, incidence and possibly response to current therapies exist between black and white patients with renal cell carcinoma (RCC). Recent genomic evidence to account for these disparities has been reported for clear cell RCC. However, racial disparities at the genomic level for papillary RCC (pRCC) which is a genetically distinct and less responsive histologic subtype of RCC have not been reported. Using The Cancer Genome Atlas (TCGA) data, the present study assessed gene-level expression, somatic mutation and pathway differences between 58 black and 58 white patients with pRCC propensity matched on age, gender and pathologic T stage. Distinct tumor biology with differential expression patterns were observed in black vs. white patients with pRCC. Specifically, significance analysis of microarrays was applied to TCGA gene expression data and identified 163 genes and 120 genes overexpressed in black and white patients, respectively (FDR q<0.05). Gene Set Enrichment Analysis identified 62 gene sets enriched (p<0.10) in blacks. Enrichment of immune immune system pathways were noted in black patients. These included the B cell receptor signaling pathway, the NOD-like receptor signaling pathway and genes involved in defensins. The VEGF pathway was also more significant in black patients. CRYBB2, a gene associated with the WNT pathway was overexpressed in Black patients. While our data requires validation, these findings suggest that race may have implications for distinct immune responses to cancer and that the use of immunotherapies, and VEGFR inhibitors to target these pathways may improve survival in black patients with advanced pRCC.

Overall survival in renal cell carcinoma after introduction of targeted therapies: a Norwegian population-based study

BACKGROUND

This population-wide retrospective, non-interventional registry study assessed changes in overall survival (OS) and factors influencing OS in Norwegian patients with renal cell carcinoma (RCC).

METHODS

Two population-wide health registries were used to identify all RCC patients with (mRCC) or without metastases diagnosed before (2002-2005) and after (2006-2008 and 2009-2011) introduction of targeted therapies. Median OS was estimated using Kaplan-Meier method. Cox proportional hazards regression modeling was used to identify prognostic factors.

RESULTS

Overall, 5,463 patients were diagnosed with RCC during 2002-2005 (n=1,898), 2006-2008 (n=1,631), and 2009-2011 (n=1,934); of these, 1,678 (31%) had mRCC. Patients diagnosed in 2009-2011 and 2006-2008 had significant (P<0.001) improvements in OS versus those diagnosed in 2002-2005: median OS, not reached and not reached versus 82.0 months in RCC; 14.0 and 12.0 months versus 9.0 months in mRCC. Similarly, OS improvements were seen in the primary and elderly (≥75 years) mRCC populations. Median OS was comparable (12 months) between clear cell and papillary mRCC, but it was longer (24.0 months) for chromophobe mRCC. Multivariate regression analyses showed that younger age, previous nephrectomy, and 1 or more prescriptions of targeted therapy were significantly associated with longer OS in mRCC patients.

CONCLUSION

OS increased in RCC and mRCC patients in Norway between 2002 and 2011 following introduction of targeted therapies.

Molecular analysis of aggressive renal cell carcinoma with unclassified histology reveals distinct subsets

Renal cell carcinomas with unclassified histology (uRCC) constitute a significant portion of aggressive non-clear cell renal cell carcinomas that have no standard therapy. The oncogenic drivers in these tumours are unknown. Here we perform a molecular analysis of 62 high-grade primary uRCC, incorporating targeted cancer gene sequencing, RNA sequencing, single-nucleotide polymorphism array, fluorescence in situ hybridization, immunohistochemistry and cell-based assays. We identify recurrent somatic mutations in 29 genes, including NF2 (18%), SETD2 (18%), BAP1 (13%), KMT2C (10%) and MTOR (8%). Integrated analysis reveals a subset of 26% uRCC characterized by NF2 loss, dysregulated Hippo–YAP pathway and worse survival, whereas 21% uRCC with mutations of MTOR, TSC1, TSC2 or PTEN and hyperactive mTORC1 signalling are associated with better clinical outcome. FH deficiency (6%), chromatin/DNA damage regulator mutations (21%) and ALK translocation (2%) distinguish additional cases. Altogether, this study reveals distinct molecular subsets for 76% of our uRCC cohort, which could have diagnostic and therapeutic implications.

A subset of renal cell carcinomas have uncertain histology and are aggressive in nature. Here, the authors examine this group of unclassified renal cancers using genomics techniques and identify further subclasses of the tumours that have differing prognoses.

Mammalian target of rapamycin is required for phrenic long-term facilitation following severe but not moderate acute intermittent hypoxia

Phrenic long-term facilitation (pLTF) is a persistent increase in phrenic nerve activity after acute intermittent hypoxia (AIH). Distinct cell-signaling cascades give rise to pLTF depending on the severity of hypoxemia within hypoxic episodes. Moderate AIH (mAIH; three 5-min episodes, PaO2 ∼35-55 mmHG) elicits pLTF by a serotonin (5-HT)-dependent mechanism that requires new synthesis of brain-derived neurotrophic factor (BDNF), activation of its high-affinity receptor (TrkB), and ERK MAPK signaling. In contrast, severe AIH (sAIH; three 5-min episodes, PaO2 ∼25-30 mmHG) elicits pLTF by an adenosine-dependent mechanism that requires new TrkB synthesis and Akt signaling. Although both mechanisms require spinal protein synthesis, the newly synthesized proteins are distinct, as are the neurochemicals inducing plasticity (serotonin vs. adenosine). In many forms of neuroplasticity, new protein synthesis requires translational regulation via mammalian target of rapamycin (mTOR) signaling. Since Akt regulates mTOR activity, we hypothesized that mTOR activity is necessary for sAIH- but not mAIH-induced pLTF. Phrenic nerve activity in anesthetized, paralyzed, and ventilated rats was recorded before, during, and 60 min after mAIH or sAIH. Rats were pretreated with intrathecal injections of 20% DMSO (vehicle controls) or rapamycin (0.1 mM, 12 μl), a selective mTOR complex 1 inhibitor. Consistent with our hypothesis, rapamycin blocked sAIH- but not mAIH-induced pLTF. Thus spinal mTOR activity is required for adenosine-dependent (sAIH) but not serotonin-dependent (mAIH) pLTF, suggesting that distinct mechanisms regulate new protein synthesis in these forms of spinal neuroplasticity.