Targeted therapies and the treatment of non-clear cell renal cell carcinoma

Impact of MET status on treatment outcomes in papillary renal cell carcinoma: A pooled analysis of historical data

BACKGROUND

Papillary renal cell carcinoma (PRCC) represents 15% of RCCs but has no indicated therapies, with limited biomarker-based data to inform targeted treatment. MET alterations may be key; > 80% of PRCC tumours show MET upregulation. The objective of this study was to assess MET status in PRCC and its impact on clinical outcomes.

METHODS

This retrospective, observational study included patients with locally advanced/metastatic PRCC from three international registries. MET status was determined retrospectively by next generation sequencing (NGS) of archival tissue. MET-driven was defined as MET and/or hepatocyte growth factor amplification, chromosome 7 gain, and/or MET kinase domain mutations. Objectives included progression-free survival (PFS) and overall survival (OS) by MET status using a Cox proportional hazards model.

RESULTS

Of 308 patients, 305 received first-line treatment; most commonly sunitinib (n = 208; 68%), then everolimus (n = 40; 13%). Of 179 patients with valid NGS results, 38% had MET-driven and 49% MET-independent tumours (13% unevaluable). In the MET-driven versus MET-independent subgroups, respectively, of sunitinib-treated patients, median PFS was numerically longer, though not statistically significantly; PFS: 9.2 months (95% confidence interval [CI]: 5.4-13.2) versus 5.7 months (95% CI: 4.3-7.4), hazard ratio (HR) = 0.67; 95% CI: 0.41-1.08. There was no difference between the OS of each subgroup.

CONCLUSIONS

MET-driven PRCC may respond to targeted agents. However, the presence of MET alterations did not appear to be predictive for outcomes in response to current therapies, which are not biomarker-driven, compared with MET-independent tumours.

Effects of Angelica Fritillaria Kushen Pill on Renal Function and Immune Function after Laparoscopic Radical Nephrectomy for Patients with Renal Carcinoma

Objective

To investigate the effect of Danggui Beimu Kushen Pills on renal cell carcinoma patients undergoing laparoscopic radical resection and their effects on renal function and immune function.

Methods

106 patients with renal cell carcinoma who underwent retroperitoneal laparoscopic radical surgery in our hospital from March 2015 to February 2017 were selected, and they were divided into control group and treatment group. The control group was treated with interferon and the treatment group was treated with Danggui Beimu Kushen pills on the basis of the control group. The clinical efficacy, incidence of adverse reactions, survival rate, and the relationship with clinical stages were detected in the two groups. The renal function index levels, immune function index levels, and quality of life levels were measured in the two groups after treatment.

Results

Compared with the control group, the total clinical effective rate was increased, the abnormal renal function, abnormal liver function, and platelet decline were decreased, and the survival rate was significantly elevated in the treatment group. The patients with clinical stage I∼II' survival rate was increased, relative to patients with clinical stage III. After treatment, the levels of β2-MG, SCr, BUN, and CD8+ in the two groups were decreased, while the levels of CD3+, CD4+, and CD4+/CD8+ were increased. Moreover, the scores of physical function, social function, emotional function, role function, cognitive function, and total score of the two groups were improved. Compared with the control group, the treatment group changes were more obvious.

Conclusion

The Danggui Beimu Kushen Pill has significant clinical effects on the treatment of renal cancer, which can improve the clinical symptoms, enhance the immune function, restore the health renal function, improve the quality of life, prolong the survival time of patients, reduce the incidence of adverse reactions, and provide high safety.

Angiogenesis Inhibitors and Immunomodulation in Renal Cell Cancers: The Past, Present, and Future

Angiogenesis inhibitors have been adopted into the standard armamentarium of therapies for advanced-stage renal cell carcinomas (RCC), but more recently, combination regimens with immune checkpoint inhibitors have demonstrated better outcomes. Despite this, the majority of affected patients still eventually experience progressive disease due to therapeutic resistance mechanisms, and there remains a need to develop novel therapeutic strategies. This article will review the synergistic mechanisms behind angiogenesis and immunomodulation in the tumor microenvironment and discuss the pre-clinical and clinical evidence for both clear-cell and non-clear-cell RCC, exploring opportunities for future growth in this exciting area of drug development.

Heterogeneity of tumor microenvironment is associated with clinical prognosis of non-clear cell renal cell carcinoma: a single-cell genomics study

Non-clear renal cell carcinomas (nccRCCs) are less frequent in kidney cancer with histopathological heterogeneity. A better understanding of the tumor biology of nccRCC can provide more effective treatment paradigms for different subtypes. To reveal the heterogeneity of tumor microenvironment (TME) in nccRCC, we performed 10x sing-cell genomics on tumor and normal tissues from patients with papillary renal cell carcinoma (pRCC), chromophobe RCC (chrRCC), collecting duct carcinoma (CDRCC) and sarcomatoid RCC (sarRCC). 15 tissue samples were finally included. 34561 cells were identified as 16 major cell clusters with 34 cell subtypes. Our study presented the sing-cell landscape for four types of nccRCC, and demonstrated that CD8+ T cells exhaustion, tumor-associated macrophages (TAMs) and sarcomatoid process were the pivotal factors in immunosuppression of nccRCC tissues and were closely correlated with poor prognosis. Abnormal metabolic patterns were present in both cancer cells and tumor-infiltrating stromal cells, such as fibroblasts and endothelial cells. Combined with CIBERSORTx tool, the expression data of bulk RNA-seq from TCGA were labeled with cell types of our sing-cell data. Calculation of the relative abundance of cell types revealed that greater proportion of exhausted CD8+ T cells, TAMs and sarRCC derived cells were correlated with poor prognosis in the cohort of 274 nccRCC patients. To the best of our knowledge, this is the first study that provides a more comprehensive sight about the heterogeneity and tumor biology of nccRCC, which may potentially facilitate the development of more effective therapies for nccRCC.

Prognostic Values of E2F1/2 Transcriptional Expressions in Chromophobe Renal Cell Carcinoma Patients: Evidence from Bioinformatics Analysis

Background

Numerous studies on the E2F transcription factors have led to increasing insights that E2Fs could be an important driver of the formation and progression of many human cancers. Little is known about the function of distinct E2Fs in chromophobe renal cell carcinoma (chRCC).

Methods

We utilized the UALCAN, GEPIA, Cancer Genome Atlas (TCGA) database, cBioPortal, Metascape, STRING, Cytoscape, GeneMANIA, TIMER, TISIDB, GSCALite, and MEXPRESS databases to investigate the transcription level, genetic alteration, methylation, and biological function of E2Fs in chRCC patients, and its association with the occurrence, progress, prognosis, and immune cell infiltration in patients with chRCC.

Results

We found that E2F1/2/4/7/8 were more expressed in chRCC tissues than in normal tissues, while the expression of E2F5/6 was lower in the former than in the latter, and the expression levels of E2F1/2/4/5/6//7/8 were also associated with the histological parameters of chRCC, including T-stage and N-stage. Higher expression of E2F1/2/7/8 was found to be significantly correlated with worse overall survival (OS) in chRCC patients. Cox regression and time-dependent ROC analysis further suggested that E2F1/2 could be the potential independent biomarkers for chRCC prognosis. Besides, a moderate mutation rate of E2Fs (34%) was noticed in chRCC, and the genetic mutations in E2Fs were associated with poor survival of chRCC patients. We noticed that the expression of E2Fs was statistically correlated with the immune cell infiltration in chRCC. Moreover, we also found that the expression of E2F1 was significantly correlated with tumor-infiltrating lymphocytes and immunomodulators, E2F7 expression was associated with MHC molecules, and the expression of E2F1/8 was correlated to their methylation levels.

Conclusion

Our results provide novel insights for selecting the prognostic biomarkers for chRCC and suggest that E2F1/2 could act as potential prognostic biomarkers for the survival of chRCC patients. However, more in-depth experiments are required to identify the underlying mechanisms and verify the clinical value of E2F1/2 in the prognosis of chRCC.

Radiomics models based on enhanced computed tomography to distinguish clear cell from non-clear cell renal cell carcinomas

This study was to assess the effect of the predictive model for distinguishing clear cell RCC (ccRCC) from non-clear cell RCC (non-ccRCC) by establishing predictive radiomic models based on enhanced-computed tomography (CT) images of renal cell carcinoma (RCC). A total of 190 cases with RCC confirmed by pathology were retrospectively analyzed, with the patients being randomly divided into two groups, including the training set and testing set according to the ratio of 7:3. A total of 396 radiomic features were computationally obtained and analyzed with the Correlation between features, Univariate Logistics and Multivariate Logistics. Finally, 4 features were selected, and three machine models (Random Forest (RF), Support Vector Machine (SVM) and Logistic Regression (LR)) were established to discriminate RCC subtypes. The radiomics performance was compared with that of radiologist diagnosis. In the testing set, the RF model had an area under the curve (AUC) value of 0.909, a sensitivity of 0.956, and a specificity of 0.538. The SVM model had an AUC value of 0.841, a sensitivity of 1.0, and a specificity of 0.231, in the testing set. The LR model had an AUC value of 0.906, a sensitivity of 0.956, and a specificity of 0.692, in the testing set. The sensitivity and specificity of radiologist diagnosis to differentiate ccRCC from non-ccRCC were 0.850 and 0.581, respectively, with the AUC value of the radiologist diagnosis as 0.69. In conclusion, radiomics models based on CT imaging data show promise for augmenting radiological diagnosis in renal cancer, especially for differentiating ccRCC from non-ccRCC.

Cabozantinib and dasatinib synergize to induce tumor regression in non-clear cell renal cell carcinoma

The lack of effective treatment options for advanced non-clear cell renal cell carcinoma (NCCRCC) is a critical unmet clinical need. Applying a high-throughput drug screen to multiple human kidney cancer cells, we identify the combination of the VEGFR-MET inhibitor cabozantinib and the SRC inhibitor dasatinib acts synergistically in cells to markedly reduce cell viability. Importantly, the combination is well tolerated and causes tumor regression in vivo. Transcriptional and phosphoproteomic profiling reveals that the combination converges to downregulate the MAPK-ERK signaling pathway, a result not predicted by single-agent analysis alone. Correspondingly, the addition of a MEK inhibitor synergizes with either dasatinib or cabozantinib to increase its efficacy. This study, by using approved, clinically relevant drugs, provides the rationale for the design of effective combination treatments in NCCRCC that can be rapidly translated to the clinic.

Adjuvant therapy in renal cell carcinoma: Current knowledges and future perspectives

While many patients with non-metastatic renal cell carcinoma (RCC) can be cured with surgery alone, upward of 40% of patients recur in a short delay, raising the question of additional perioperative treatments. To address this clinical need, multiple trials have investigated the addition of systemic therapy after surgery in localized or locally advanced RCC. However, adjuvant systemic therapies in the past decades have provided disappointing results with only one positive study of antiangiogenic treatments. Debatable clinical benefit of adjuvant antiangiogenic tyrosine kinase inhibitors (TKIs) therapy at cost of high adverse event profiles have paved the way for development of alternative perioperative strategies, such as immune checkpoint inhibitors (ICIs). Further investigation into combination therapies with immunotherapy, neoadjuvant approaches and patient selection will be key to determining optimal adjuvant therapy regimens to improve outcomes and increase cure rates for patients with non-metastatic RCC. In this review, we extensively present the strong and weakness of the five adjuvant antiangiogenic TKI trials, highlight the main differences and discuss about the reasons of failure. We also expose the current ongoing clinical trials in the perioperative setting and provide new insights concerning the evolving landscape of the management of non-metastatic RCC.

Are tyrosine kinase inhibitors fit for purpose in the treatment of metastatic papillary renal cell carcinoma?

Renal cell carcinoma encompasses a range of histological subtypes. The treatment of metastatic disease in this context remains challenging. Papillary renal cell carcinoma is the second most common subtype and forms a significant subsection of non-clear cell renal cell carcinoma. Tyrosine kinase inhibitors form a significant part of the treatment of this largely incurable disease; however, outcomes tend to be poor. The aim of this article is to scrutinise whether these treatments are evidence-based in their use for metastatic papillary renal cell carcinoma and if good outcomes are reported. A literature review was made using PubMed of major prospective and retrospective studies. The European Association of Urology and European Society of Medical Oncology have both published guidance suggesting sunitinib should be offered first line in the treatment of metastatic papillary renal cell carcinoma. This, however, is based upon weak evidence produced by the ASPEN trial, although this did not discriminate between non-clear cell subtypes and results in further studies were modest. The National Institute for Care and Health Excellence has recently published new guidelines for the use of cabozantinib, which has shown evidence of improved progression-free survival and overall response rates compared with sunitinib. Unfortunately, many of the relevant studies did not specifically assess these treatments in patients solely with papillary renal cell carcinoma and had modest overall success. There is weak evidence that tyrosine kinase inhibitors give significant benefit in those patients with metastatic papillary renal cell carcinoma.

Level of evidence: 2a

Efficacy of Savolitinib vs Sunitinib in Patients With MET-Driven Papillary Renal Cell Carcinoma: The SAVOIR Phase 3 Randomized Clinical Trial

Importance

Papillary renal cell carcinoma (PRCC) is the most common type of non-clear cell RCC. Because some cases of PRCC are MET-driven, MET inhibition could be a targeted treatment approach. In previous studies, savolitinib (AZD6094, HMPL-504, volitinib), a highly selective MET-tyrosine kinase inhibitor, demonstrated antitumor activity in this patient group.

Objective

To determine whether savolitinib is a better treatment option for this patient population, vs standard of care, sunitinib.

Design, Setting, and Participants

The SAVOIR phase 3, open-label, randomized clinical trial was a multicenter study carried out in 32 centers in 7 countries between July 2017 and the data cutoff in August 2019. Overall, 360 to 450 patients were to be screened to randomize approximately 180 patients. Patients were adults with MET-driven (centrally confirmed), metastatic PRCC, with 1 or more measurable lesions. Exclusion criteria included prior receipt of sunitinib or MET inhibitor treatment. Overall, 254 patients were screened.

Interventions

Patients received 600 mg of savolitinib orally once daily (qd), or 50 mg of sunitinib orally qd for 4 weeks, followed by 2 weeks without treatment.

Main Outcomes and Measures

The primary end point was progression-free survival (PFS, assessed by investigator and confirmed by blinded independent central review). Secondary end points included overall survival (OS), objective response rate (ORR), duration of response, and safety/tolerability.

Results

At data cutoff, 60 patients were randomized (savolitinib n = 33; sunitinib n = 27); most patients had chromosome 7 gain (savolitinib, 30 [91%]; sunitinib, 26 [96%]) and no prior therapy (savolitinib, 28 [85%]; sunitinib, 25 [93%]). For savolitinib and sunitinib, 4 (12%) and 10 (37%) patients were women, and the median (range) age was 60 (23-78) and 65 (31-77) years, respectively. Following availability of external data on PFS with sunitinib in patients with MET-driven disease, study enrollment was closed. Progression-free survival, OS, and ORR were numerically greater with savolitinib vs sunitinib. Median PFS was not statistically different between the 2 groups: 7.0 months (95% CI, 2.8-not calculated) for savolitinib and 5.6 months (95% CI, 4.1-6.9) for sunitinib (hazard ratio [HR], 0.71; 95% CI, 0.37-1.36; P = .31). For savolitinib and sunitinib respectively, grade 3 or higher adverse events (AEs) were reported in 14 (42%) and 22 (81%) of patients and AE-related dose modifications in 10 (30%) and 20 (74%). After discontinuation, 12 (36%) and 5 (19%) of patients on savolitinib and sunitinib respectively, received subsequent anticancer therapy.

Conclusions and Relevance

Although patient numbers and follow-up were limited, savolitinib demonstrated encouraging efficacy vs sunitinib, with fewer grade 3 or higher AEs and dose modifications. Further investigation of savolitinib as a treatment option for MET-driven PRCC is warranted.

Trial Registration

ClinicalTrials.gov Identifier: NCT03091192.

Computational analysis of pathological images enables a better diagnosis of TFE3 Xp11.2 translocation renal cell carcinoma

TFE3 Xp11.2 translocation renal cell carcinoma (TFE3-RCC) generally progresses more aggressively compared with other RCC subtypes, but it is challenging to diagnose TFE3-RCC by traditional visual inspection of pathological images. In this study, we collect hematoxylin and eosin- stained histopathology whole-slide images of 74 TFE3-RCC cases (the largest cohort to date) and 74 clear cell RCC cases (ccRCC, the most common RCC subtype) with matched gender and tumor grade. An automatic computational pipeline is implemented to extract image features. Comparative study identifies 52 image features with significant differences between TFE3-RCC and ccRCC. Machine learning models are built to distinguish TFE3-RCC from ccRCC. Tests of the classification models on an external validation set reveal high accuracy with areas under ROC curve ranging from 0.842 to 0.894. Our results suggest that automatically derived image features can capture subtle morphological differences between TFE3-RCC and ccRCC and contribute to a potential guideline for TFE3-RCC diagnosis.

Translocation renal cell carcinoma is an aggressive form of renal cancer that is often misdiagnosed to other subtypes. Here the authors demonstrated that by using machine learning and H&E stained whole-slide images, an accurate diagnose of this particular type of renal cancer can be achieved.

PD-L1 expression and infiltration by CD4+ and FoxP3+ T cells are increased in Xp11 translocation renal cell carcinoma and indicate poor prognosis

AIMS

Interaction between programmed death-1 ligand (PD-L1) and its receptor programmed death 1 (PD-1) on T cells inactivates antitumour immune responses. PD-L1 expression has been associated with poor prognosis in renal cell carcinoma (RCC) and predicts adverse outcome. This study was designed to evaluate the impact of PD-L1 expression and the immune microenvironment on the clinical outcome in Xp11 translocation renal cell carcinoma (TRCC) and, therefore, their potential relevance as prognostic biomarkers.

METHODS AND RESULTS

The present retrospective analysis investigated expression of PD-L1 and immune cells CD8, CD4, CD3, forkhead box protein 3 (FoxP3) and PD-1 in TRCC compared to other types of RCC. FFPE specimens were collected between 2011 and 2017 from 311 patients who underwent nephrectomy at our institution for RCC. Specimens were immunostained for PD-L1, CD8, CD4, CD3, FoxP3 and PD-1, and an outcome analysis was conducted. PD-L1 expression rate was highest in TRCC (68%, 16 of 25), followed by mucinous tubular and spindle cell RCC and collecting duct carcinoma (33%, one of three), papillary RCC (27%, seven of 26), clear cell RCC (16%, 29 of 233), chromophobe RCC (11%, two of 18) and multilocular cystic RCC (0%, none of three). In TRCC, PD-L1 expression was associated with poor recurrence-free survival (RFS) (P = 0.041). The CD4^high and FoxP3^high groups showed a significantly shorter RFS (P = 0.05 and P = 0.031, respectively) compared to CD4^low and FOXP^low groups.

CONCLUSION

PD-L1 expression was higher in TRCC than in other types of RCC. High PD-L1 tumour cell expression and tumour infiltration by CD4⁺ and FoxP3⁺ immune cells were associated with poor RFS in TRCC.

[Why have tyrosine kinase inhibitors failed in the adjuvant situation and do checkpoint inhibitors make more sense?]

In view of a considerable risk of recurrence especially in patients with a high-risk profile after organ-sparing surgery or nephrectomy, adjuvant treatment seems to make sense in renal cell carcinoma. After the failed attempts using older immunotherapeutics or vaccination therapies, new hope was put in the panel of targeted VEGF/R inhibitors. But the results from these studies published so far are also disappointing. In this context the instruments for selecting the best suitable patients for adjuvant trials have to be discussed. It remains to be seen whether using the same selection criteria as in ongoing trials with checkpoint inhibitors will show better results.

Comparison of three risk stratification models for non-clear cell renal cell carcinoma patients treated with temsirolimus as first-line therapy

BACKGROUND/AIMS

For metastatic renal cell carcinoma (RCC), various prognostic scoring systems have been developed. However, owing to the low prevalence of nonclear cell RCC, the three most commonly used tools were mainly developed based on patients with clear cell histology. Accordingly, this study applied three prognostic models to Korean non-clear cell RCC patients treated with first-line temsirolimus.

METHODS

This study analyzed data for 74 patients with non-clear cell RCC who were treated with temsirolimus as the first-line therapy at eight medical centers between 2011 and 2016. The receiver-operating characteristic (ROC) curves for the different prognostic models were analyzed.

RESULTS

Twenty-seven (36.5%), 24 (32.4%), and 44 patients (59.5%) were assigned to the poor prognosis groups of the Memorial Sloan-Kettering Cancer Center (MSKCC), International Metastatic RCC Database Consortium (IMDC), and Advanced Renal Cell Carcinoma (ARCC) risk stratification models, respectively. All three prognostic models reliably discriminated the risk groups to predict progression-free survival and overall survival (p < 0.001). The area under the ROC curve (AUC) for progression and survival was highest for the ARCC model (0.777; 0.734), followed by the IMDC (0.756; 0.724) and the MSKCC (0.742; 0.712) models. Furthermore, the sensitivity and specificity for predicting progression were highest with the ARCC model (sensitivity 63.6%, specificity 85.7%), followed by the MSKCC (sensitivity 58.2%, specificity 86.5%) and the IMDC models (sensitivity 56.4%, specificity 85.7%).

CONCLUSION

All three prognostic models accurately predicted the survival of the non-clear cell RCC patients treated with temsirolimus as the first-line therapy. Furthermore, the ARCC risk model performed better than the other risk models in predicting survival.

Safety and Efficacy of Cabozantinib for Metastatic Nonclear Renal Cell Carcinoma: Real-world Data From an Italian Managed Access Program

OBJECTIVE

The activity of cabozantinib in nonclear cell histologies has not been evaluated.

MATERIALS AND METHODS

Data were collected across 24 Italian hospitals. Patients were aged 18 years and older with advanced nonclear cell renal cell carcinoma (RCC), with an Eastern Cooperative Oncology Group Performance Status 0 to 2, who had relapsed after previous systemic treatments for metastatic disease. Cabozantinib was administered orally at 60 mg once a day in 28 days cycles. Dose reductions to 40 or 20 mg were made due to toxicity. Adverse events (AEs) were monitored using CTCAE version 4.0.

RESULTS

Seventeen patients were enrolled. Three (18%) patients were diagnosed type I papillary RCC, 9 (53%) type II papillary, 3 (18%) chromophobe, and 2 (11%) with Bellini duct carcinoma. In total, 11 patients started with 60 mg. Six patients started a lower dose of 40 mg. Median progression-free survival was 7.83 months (0.4 to 13.4 mo), while median overall survival was not reached but 1-year overall survival was about 60%. Six patients (35%) experienced a partial response to treatment and 6 patients (35%) showed a stable disease. In the remaining 5 (30%), we observed a progressive disease. Grade 3 and 4 AEs were observed in 41% of patients. Among 20 patients, only 1 (6%) discontinued treatment due to AEs. Asthenia (41%), diarrhea (35%), aminotransferase increasing (35%), mucosal inflammation (35%), hand and foot syndrome (24%), and hypothyroidism (24%) were the most frequently AEs.

CONCLUSIONS

Our data showed that, cabozantinib is a active and feasible treatment in patient with nonclear cell RCC.

Clinicopathologic features associated with survival after cytoreductive nephrectomy for nonclear cell renal cell carcinoma

OBJECTIVES

To report the overall survival (OS) outcomes of patients with nonclear cell renal cell carcinoma (nccRCC) treated at our institution with a cytoreductive nephrectomy (CN) and better understand the clinical and pathological characteristics of the patients that respond best.

MATERIAL AND METHODS

We queried our prospectively maintained database for patients who underwent CN for nccRCC between 1989 and 2018. Histology was reviewed by an expert genitourinary pathologist, and nccRCC tumors were subdivided into papillary, unclassified, chromophobe, and other histology. Baseline clinicopathology, treatments, and survival outcomes were recorded. Preoperative hematological parameters including the neutrophil-to-lymphocyte ratio (NLR) were analyzed. Significant univariate predictors of OS were tested in a multivariate model.

RESULTS

There were 100 nccRCC patients treated with CN. Median age was 61 years (IQR: 48-69) and 65% were male. There were 79 patient deaths with a median OS of 13.7 months (10.8-27.2). Estimated 2- and 5-year survival was 40.1% and 12.2%, respectively. Median follow-up of survivors was 13 months (IQR: 3-30). On multivariate analysis, increasing NLR (hazard ratio [HR] 1.27; 95% confidence interval [CI] 1.14-1.40, P < 0.001) and sarcomatoid features (HR 2.18; 95% CI 1.19-3.97, P = 0.014) conferred worse OS and the presence of papillary features were a favorable prognostic feature (HR 0.37; 95% CI 0.21-0.65, P < 0.001).

CONCLUSIONS

OS outcomes in patients with nccRCC who underwent a CN are consistently modest throughout the study period. Patients with papillary features and a lower preoperative NLR may be better candidates for a CN.

Surgical treatment for Xp11.2 translocation renal cell carcinoma with venous thrombus: A STROBE-compliant study

The aim of the study was to report the experience and outcomes of Xp11.2 translocation renal cell carcinoma (tRCC) patients with tumor thrombus undergoing radical nephrectomy and thrombectomy.Between January 2017 and December 2017, 66 consecutive patients with RCC and venous thrombus involvement received surgical treatment at Peking University Third Hospital. Of which, 5 patients were confirmed of Xp11.2 tRCC, 61 patients were diagnosed of non-tRCC subtypes including 45 ccRCCs, 10 pRCCs, and 6 other subtypes. Demographic, clinical, operation, pathological and follow-up data were extracted for analysis. Prognostic factors were identified by Cox regression analysis.All the patients received radical nephrectomy and thrombectomy successfully. During a median follow-up of 18 months, 5 patients in non-tRCC group and 1 patient in tRCC group died of disease progression. Survival analysis revealed that Xp11.2 tRCC patients experienced shorter DFS than non-tRCC patients, however, there is no significant difference in OS between two groups. Xp11.2 tRCC histological subtype and presence of metastasis at diagnosis were identified as independent negative factors of DFS by multivariate analysis.Radical nephrectomy with thrombectomy provides an acceptable efficacy for tRCC patients with tumor thrombus extending into the venous system. In addition, multimodality treatment should be considered for advanced Xp11.2 RCCs as this subtype was a negative prognostic factor of DFS.

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.

Identification of biomarkers of chromophobe renal cell carcinoma by weighted gene co-expression network analysis

Background

Chromophobe renal cell carcinoma (ChRCC) is the second common subtype of non-clear cell renal cell carcinoma (nccRCC), which accounting for 4–5% of renal cell carcinoma (RCC). However, there is no effective bio-marker to predict clinical outcomes of this malignant disease. Bioinformatic methods may provide a feasible potential to solve this problem.

Methods

In this study, differentially expressed genes (DEGs) of ChRCC samples on The Cancer Genome Atlas database were filtered out to construct co-expression modules by weighted gene co-expression network analysis and the key module were identified by calculating module-trait correlations. Functional analysis was performed on the key module and candidate hub genes were screened out by co-expression and MCODE analysis. Afterwards, real hub genes were filter out in an independent dataset GSE15641 and validated by survival analysis.

Results

Overall 2215 DEGs were screened out to construct eight co-expression modules. Brown module was identified as the key module for the highest correlations with pathologic stage, neoplasm status and survival status. 29 candidate hub genes were identified. GO and KEGG analysis demonstrated most candidate genes were enriched in mitotic cell cycle. Three real hub genes (SKA1, ERCC6L, GTSE-1) were selected out after mapping candidate genes to GSE15641 and two of them (SKA1, ERCC6L) were significantly related to overall survivals of ChRCC patients.

Conclusions

In summary, our findings identified molecular markers correlated with progression and prognosis of ChRCC, which might provide new implications for improving risk evaluation, therapeutic intervention, and prognosis prediction in ChRCC patients.

Electronic supplementary material

The online version of this article (10.1186/s12935-018-0703-z) contains supplementary material, which is available to authorized users.

Caspase 3 as a Novel Marker to Distinguish Chromophobe Renal Cell Carcinoma from Oncocytoma

Despite advances in our understanding of the biology of chromophobe renal cell carcinoma (ChRCC) and renal oncocytoma (RO), the differential diagnosis among these tumors remains one of the most problematic in renal pathology. Today, CK7 is the most recommended marker to distinguish these entities, however it appears insufficiently accurate by itself. This study aimed to find an easily accessible IHC stain that might out-compete CK7 in this field. Expressions of CK7, cyclin D1, p16, survivin, CD138, Ki-67 and caspase 3 (CASP3) were analyzed in a total of 27 cases (20 ROs and 7 ChRCCs). Immunoreactivity was assessed based on a combined score of the extent and intensity of staining. Compared to RO, a higher percentage of the total ChRCCs stained positive for CK7 (67% vs. 22%, respectively) and CASP3 (86% vs. 25%) (P < 0.005). The differences in staining with cyclin D1, p16, survivin, CD138 and Ki-67 turned out to be statistically insignificant in differentiating ChRCC from RO. CASP3 is a promising marker in distinguishing ChRCC from RO and may represent an alternative for CK7. Cyclin D1, p16, survivin, CD138 and Ki-67 cannot be used to distinguish these neoplasms.

Immune checkpoint inhibitors in renal cell carcinoma

The immune system has long been known to play a critical role in the body's defence against cancer, and there have been multiple attempts to harness it for therapeutic gain. Renal cancer was, historically, one of a small number of tumour types where immune manipulation had been shown to be effective. The current generation of immune checkpoint inhibitors are rapidly entering into routine clinical practice in the management of a number of tumour types, including renal cancer, where one drug, nivolumab, an anti-programmed death-1 (PD-1) monoclonal antibody (mAb), is licensed for patients who have progressed on prior systemic treatment. Ongoing trials aim to maximize the benefits that can be gained from this new class of drug by exploring optimal timing in the natural course of the disease as well as combinations with other checkpoint inhibitors and drugs from different classes.

Morphological spectrum of renal cell carcinoma, unclassified: an analysis of 136 cases

AIMS

Renal cell carcinoma, unclassified (RCCU) is a category that includes a morphologically and biologically heterogeneous group of tumours that are unable to be diagnosed as other well-defined entities. We aim to describe the morphological findings of tumours within this category and to determine the most frequent morphological features leading to classification difficulty.

METHODS AND RESULTS

One hundred and thirty-six cases of RCCU were examined. Patients ranged in age from 23 to 87 years. Seventy-seven patients were men and 59 were women. International Society of Urological Pathology (ISUP) grade was most commonly 3 (n = 66), followed by 2 (n = 42) and 4 (n = 28). Tumour size ranged from 0.6 to 24.9 cm. The American Joint Committee on Cancer (AJCC) pathological T categories included pT1a (n = 50), pT1b (n = 14), pT2a (n = 7), pT2b (n = 4), pT3a (n = 50) and pT4 (n = 9). Forty-four cases included lymph node(s), 41% of which (n = 18) had metastases. Tumours were assessed for a variety of histological features and assigned to the following morphological groups: predominantly oncocytoma/chromophobe RCC-like; clear cell RCC-like; papillary RCC-like; collecting duct-like; and pure sarcomatoid differentiation. The majority of the oncocytoma/chromophobe and clear cell RCC-like phenotypes were low stage (pT1 or pT2). The papillary RCC-like, collecting duct-like and pure sarcomatoid phenotypes were mainly high stage (pT3 or pT4).

CONCLUSIONS

Renal cell carcinoma, unclassified is a term that encompasses tumours with a variety of morphological features and a wide biological spectrum. The most common source of diagnostic difficulty was tumours composed of predominantly eosinophilic cells.

Current Clinical Practice Guidelines for the Treatment of Renal Cell Carcinoma: A Systematic Review and Critical Evaluation

The landscape of local and systemic therapy of renal cell carcinoma (RCC) is rapidly changing. The increase in the incidental finding of small renal tumors has increased the application of nephron-sparing procedures, while ten novel agents targeting the vascular endothelial growth factor (VEGF) or the mammalian target of rapamycin pathways, or inhibiting the interaction of the programmed death 1 receptor with its ligand, have been approved since 2006 and have dramatically improved the prognosis of metastatic RCC (mRCC). These rapid developments have resulted in continuous changes in the respective Clinical Practice Guidelines/Expert Recommendations. We conducted a systematic review of the existing guidelines in MEDLINE according to the Preferred Reporting Items for Systematic Review and Meta-Analyses statement, aiming to identify areas of agreement and discrepancy among them and to evaluate the underlying reasons for such discrepancies. Data synthesis identified selection criteria for nonsurgical approaches in renal masses; the role of modern laparoscopic techniques in the context of partial nephrectomy; selection criteria for cytoreductive nephrectomy and metastasectomy in mRCC; systemic therapy of metastatic non-clear-cell renal cancers; and optimal sequence of available agents in mRCC relapsed after anti-VEGF therapy as the major areas of uncertainty. Agreement or uncertainty was not always correlated with the availability of data from phase III randomized controlled trials. Our review suggests that the combination of systematic review and critical evaluation can define practices of wide applicability and areas for future research by identifying areas of agreement and uncertainty among existing guidelines.

IMPLICATIONS FOR PRACTICE

Currently, there is uncertainity on the role of surgery in MRCC and on the choice of available guidelines in relapsed RCC. The best practice is individualization of targeted therapies. Systematic review of guidelines can help to identify unmet medical needs and areas of future research.

Adjuvant Therapy for High Risk Localized Kidney Cancer: Emerging Evidence and Future Clinical Trials

PURPOSE

We reviewed the literature on adjuvant therapies for patients with high risk localized kidney cancer following surgical resection. In this analysis we merge 2 recently published prospective trials with conflicting results within the context of their respective designs. In addition, we spotlight upcoming trials that use novel immunotherapy based checkpoint inhibitors and have the potential to establish a new standard of care.

MATERIALS AND METHODS

We searched PubMed^® for English language articles published through January 2017 using the keywords "renal cell carcinoma," "kidney cancer," "immunotherapy," "targeted therapy" and "adjuvant therapy." ClinicalTrials.gov was queried for ongoing studies. Relevant data recently presented at major urology and medical oncology meetings are also included.

RESULTS

Adjuvant therapies for high risk localized kidney cancer can be grouped into the categories of 1) traditional immunotherapy, 2) inhibitors of the vascular endothelial growth factor and mTOR (mammalian target of rapamycin) pathways, 3) vaccines and antibody dependent cytotoxic agents, and 4) immune checkpoint inhibitors. Several trials of traditional immunotherapy, such as interferon-α and high dose interleukin-2, failed to demonstrate benefit as adjuvant treatment and were associated with significant adverse events. Vascular endothelial growth factor and mTOR inhibitors have less severe toxicity in metastatic disease and, therefore, are natural considerations for adjuvant trials. However, current data are conflicting. The ASSURE (Sunitinib Malate or Sorafenib Tosylate in Treating Patients with Kidney Cancer that was Removed by Surgery, NCT00326898) trial found no recurrence-free survival benefit of sorafenib or sunitinib over placebo, while S-TRAC (Clinical Trial Comparing Efficacy and Safety of Sunitinib versus Placebo for the Treatment of Patients at High Risk of Recurrent Renal Cell Cancer, NCT00375674) revealed that 1 year of sunitinib improved recurrence-free survival by 1.2 years. Vaccine based treatments and antibody dependent cytotoxic agents have had mixed results. New trials evaluating immune checkpoint inhibitors are planned, given the impressive efficacy and tolerability as second line agents in metastatic disease. Future adjuvant trials are likely to be guided by molecular signatures to treat patients most likely to benefit.

CONCLUSIONS

Based on the available data, there appears to be no role for traditional immunotherapy as adjuvant treatment in patients with high risk localized kidney cancer following surgical resection. S-TRAC provides evidence that 1 year of adjuvant sunitinib in patients with higher risk locoregional disease increases the median time to recurrence. However, the data on overall survival are immature and adverse effects are common. Results from trials investigating immune checkpoint inhibitors are highly anticipated.

Society for Immunotherapy of Cancer consensus statement on immunotherapy for the treatment of renal cell carcinoma

Immunotherapy has produced durable clinical benefit in patients with metastatic renal cell cancer (RCC). In the past, patients treated with interferon-alpha (IFN) and interleukin-2 (IL-2) have achieved complete responses, many of which have lasted for multiple decades. More recently, a large number of new agents have been approved for RCC, several of which attack tumor angiogenesis by inhibiting vascular endothelial growth factors (VEGF) and VEGF receptors (VEGFR), as well as tumor metabolism, inhibiting the mammalian target of rapamycin (mTOR). Additionally, a new class of immunotherapy agents, immune checkpoint inhibitors, is emerging and will play a significant role in the treatment of patients with RCC. Therefore, the Society for Immunotherapy of Cancer (SITC) convened a Task Force, which met to consider the current role of approved immunotherapy agents in RCC, to provide guidance to practicing clinicians by developing consensus recommendations and to set the stage for future immunotherapeutic developments in RCC.

Cabozantinib inhibits tumor growth and metastasis of a patient-derived xenograft model of papillary renal cell carcinoma with MET mutation

MET plays an important role in the development and progression of papillary renal cell carcinoma (pRCC). Evaluation of efficacy of MET inhibitors against pRCC has been hampered by limited preclinical models depicting MET abnormalities. We established a new patient-derived xenograft (PDX) model of pRCC carrying an activating mutation of MET and tested the ability of cabozantinib, an inhibitor of receptor tyrosine kinases including MET, to inhibit tumor growth and metastasis. Precision-cut, thin tissue slices from a pRCC specimen obtained by nephrectomy were implanted under the renal capsule of RAG2^-/-γC^-/- mice to establish first generation TSG-RCC-030. Histologic and genetic fidelity and metastatic potential of this model were characterized by immunohistochemistry, direct DNA sequencing and quantitative polymerase chain reaction (qPCR). The effect of cabozantinib on tumor growth and metastasis was evaluated. Whether measurements of circulating tumor DNA (ctDNA) by allele-specific qPCR could be used as a biomarker of tumor growth and response to therapy was determined. Subrenal and subcutaneous tumor grafts showed high take rates and metastasized to the lung. Both primary tumors and metastases expressed typical markers of pRCC and carried the same activating MET mutation as the parental tumor. Cabozantinib treatment caused striking tumor regression and inhibited lung metastasis in TSG-RCC-030. Plasma ctDNA levels correlated with tumor volume in control mice and changed in response to cabozantinib treatment. TSG-RCC-030 provides a realistic preclinical model to better understand the development and progression of pRCC with MET mutation and accelerate the development of new therapies for pRCC.

Management of poor-risk metastatic renal cell carcinoma: current approaches, the role of temsirolimus and future directions

Targeted therapies have substantially improved outcomes in metastatic renal cell carcinoma (mRCC). As expected, poor-risk patients have the worst outcomes. Temsirolimus is currently the only agent licensed for treatment of poor-risk mRCC patients. It is associated with meaningful improvements in survival and quality of life, highlighting the importance of correctly stratifying risk in mRCC patients so they receive optimal treatment. Currently, data for other targeted therapies in poor-risk patients are relatively sparse. Optimizing outcomes in these patients is the subject of ongoing research, including studies of biomarkers and studies to elucidate the role of nephrectomy and neoadjuvant targeted therapy in poor-risk mRCC patients. The impacts of novel combinations including temsirolimus have also been explored to further improve outcomes.

Everolimus Versus Sunitinib Prospective Evaluation in Metastatic Non-Clear Cell Renal Cell Carcinoma (ESPN): A Randomized Multicenter Phase 2 Trial

BACKGROUND

Sunitinib and everolimus are standard first-line and second-line therapies, respectively, in clear cell renal cell carcinoma (ccRCC).

OBJECTIVE

To conduct a randomized phase 2 trial comparing sunitinib and everolimus in non-clear cell RCC (non-ccRCC).

DESIGN, SETTING, AND PARTICIPANTS

Patients with metastatic, non-ccRCC, or ccRCC with >20% sarcomatoid features (ccSRCC) were randomized to receive sunitinib or everolimus with crossover at disease progression.

OUTCOME MEASUREMENT AND STATISTICAL ANALYSIS

Primary end point was progression-free survival (PFS) in first-line therapy; 108 patients were needed to show improvement in median PFS (mPFS) from 12 wk with sunitinib to 20 wk with everolimus.

RESULTS AND LIMITATIONS

Interim analysis of 68 patients (papillary [27], chromophobe [12], unclassified [10], translocation [7], ccSRCC [12]) prompted early trial closure. The mPFS in first-line therapy was 6.1 mo with sunitinib and 4.1 mo with everolimus (p=0.6); median overall survival (mOS) was not reached with sunitinib and was 10.5 mo with everolimus, respectively (p=0.014). At final analysis, mOS was 16.2 and 14.9 mo with sunitinib and everolimus, respectively (p=0.18). There were four partial responses (PRs) in first-line therapy (sunitinib: 3 of 33 [9%]; everolimus, 1 of 35 [2.8%]) and four PRs in second-line therapy (sunitinib: 2 of 21 [9.5%]; everolimus, 2 of 23 [8.6%]), with mPFS of 1.8 mo and 2.8 mo, respectively. In patients without sarcomatoid features in their tumors (n=49), mOS was 31.6 mo with sunitinib and 10.5 mo with everolimus (p=0.075). Genomic profiling of a chromophobe RCC from a patient with a PR to first-line everolimus revealed a somatic TSC2 mutation.

CONCLUSIONS

In this trial, everolimus was not superior to sunitinib. Both agents demonstrated modest efficacy, underscoring the need for better therapies in non-ccRCC.

PATIENT SUMMARY

This randomized phase 2 trial provides the first head-to-head comparison of everolimus and sunitinib in patients with metastatic non-clear cell renal cell carcinoma (non-ccRCC). The observed very modest efficacy underscores the need to develop more effective therapies for non-ccRCC.

Pathology, therapy and prognosis of papillary renal carcinoma

Papillary renal cell carcinoma (pRCC) accounts for approximately 10% of renal parenchymal tumors. There are two pRCC subtypes reported in several studies, but at present, there is limited molecular evidence to validate this pRCC subtyping in the daily routine. The utility of subtyping pRCC is based on reports describing that pRCC subtype is an independent predictor of outcome, with type 1 tumors showing significantly better survival than type 2 tumors. In this article, we summarize the relevant knowledge on pRCC regarding tumor features: clinical presentation, histopathology, electron microscopy, immunohistochemistry, cytogenetics, genetic/molecular and prognosis. We present an overview of the currently available pRCC treatment options and some of the new promising agents.

Multidisciplinary management of clear-cell renal cell carcinoma in Africa and the Middle East: current practice and recommendations for improvement

The management of renal cell carcinoma (RCC) has evolved considerably in recent years. This report represents the consensus of 22 relevant medical specialists from Africa and the Middle East region engaged in the management of RCC. Partial or radical nephrectomy is the standard of care for most patients with localized RCC. It is essential that patients are followed up appropriately after surgery to enable local and distant relapses to be identified and treated promptly. The treatment of advanced/metastatic disease has changed dramatically with the introduction of targeted therapies. Follow-up of these patients enables therapy optimization and assessment of response to treatment. There was universal agreement on the importance of management of RCC by a multidisciplinary team supported by a multidisciplinary tumor board. Barriers hindering this approach were identified. These included lack of awareness of the benefits of multidisciplinary team role, poor communication among relevant disciplines, time constraints, and specifics of private practice. Other challenges include shortage of expert specialists as urologists and oncologists and lack of local management guidelines in some countries. Solutions were proposed and discussed. Medical educational initiatives and awareness activities were highlighted as keys to encouraging cooperation between specialties to improve patients’ outcome. Establishing combined genitourinary cancer clinics and formal referral systems should encourage a culture of effective communication. Joining forces with professionals in peripheral areas and the private sector is likely to help standardize care. Sustained action will be required to ensure that all patients with RCC in the region benefit from up-to-date care.

Whole lesion quantitative CT evaluation of renal cell carcinoma: differentiation of clear cell from papillary renal cell carcinoma

Purpose

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of renal cell cancer (RCC), followed by papillary RCC (pRCC). It is important to distinguish these two subtypes because of prognostic differences and possible changes in management, especially in cases undergoing active surveillance. The purpose of our study is to evaluate the use of voxel-based whole-lesion (WL) enhancement parameters on contrast enhanced computed tomography (CECT) to distinguish ccRCC from pRCC.

Materials and methods

In this institutional review board-approved study, we retrospectively queried the surgical database for post nephrectomy patients who had pathology proven ccRCC or pRCC and who had preoperative multiphase CECT of the abdomen between June 2009 and June 2011. A total of 61 patients (46 with ccRCC and 15 with pRCC) who underwent robotic assisted partial nephrectomy for clinically localized disease were included in the study. Multiphase CT acquisitions were transferred to a dedicated three-dimensional workstation, and WL regions of interest were manually segmented. Voxel-based contrast enhancement values were collected from the lesion segmentation and displayed as a histogram. Mean and median enhancement and histogram distribution parameters skewness, kurtosis, standard deviation, and interquartile range were calculated for each lesion. Comparison between ccRCC and pRCC was made using each imaging parameter. For mean and median enhancement, which had a normal distribution, independent t-test was used. For histogram distribution parameters, which were not normally distributed, Wilcoxon rank sum test was used.

Results

ccRCC had significantly higher mean and median whole WL enhancement (p < 0.01) compared to pRCC on arterial, nephrographic, and excretory phases. ccRCC had significantly higher interquartile range and standard deviation (p < 0.01) and significantly lower skewness (p < 0.01) compared to pRCC on arterial and nephrographic phases. ccRCC had significantly lower kurtosis compared to pRCC on only the arterial phase.

Conclusion

Our study suggests that voxel-based WL enhancement parameters can be used as a quantitative tool to differentiate ccRCC from pRCC. Differentiating between the two main types of RCC would provide the patient and the treating physicians more information to formulate the initial approach to managing the patient’s renal cancer.

Spectrum of diverse genomic alterations define non-clear cell renal carcinoma subtypes

To further understand the molecular distinctions between kidney cancer subtypes, we analyzed exome, transcriptome and copy number alteration data from 167 primary human tumors that included renal oncocytomas and non-clear cell renal cell carcinomas (nccRCCs), consisting of papillary (pRCC), chromophobe (chRCC) and translocation (tRCC) subtypes. We identified ten significantly mutated genes in pRCC, including MET, NF2, SLC5A3, PNKD and CPQ. MET mutations occurred in 15% (10/65) of pRCC samples and included previously unreported recurrent activating mutations. In chRCC, we found TP53, PTEN, FAAH2, PDHB, PDXDC1 and ZNF765 to be significantly mutated. Gene expression analysis identified a five-gene set that enabled the molecular classification of chRCC, renal oncocytoma and pRCC. Using RNA sequencing, we identified previously unreported gene fusions, including ACTG1-MITF fusion. Ectopic expression of the ACTG1-MITF fusion led to cellular transformation and induced the expression of downstream target genes. Finally, we observed upregulation of the anti-apoptotic factor BIRC7 in MiTF-high RCC tumors, suggesting a potential therapeutic role for BIRC7 inhibitors.

SEOM clinical guidelines for the treatment of renal cell carcinoma

The purpose of this article was to provide updated recommendations for the diagnosis and treatment of renal cell carcinoma. Pathological confirmation is mandatory before treatment with ablative or focal therapies before any type of systemic therapy. Renal cell cancer should be staged according to the TNM classification system. A laparoscopic nephron-sparing surgery should be the approach for tumors <4 cm if technically feasible. Otherwise, radical (or partial in selected cases) nephrectomy is the treatment of choice, with lymph node dissection only performed in patients with clinically detected lymph node involvement. Some retrospective evidence for a cytoreductive nephrectomy in the postimmunotherapy era suggests a benefit in patients with good or intermediate risk or for patients with a symptomatic primary lesion. Adjuvant treatment with chemotherapy or with targeted agents is not recommended and studies are ongoing today. Patients with metastatic disease should be staged by computed tomography scans of the chest, abdomen and pelvis. The efficacy of sunitinib, bevacizumab plus interferon-α, and pazopanib is well established in patients with good and intermediate risk as well for temsirolimus in poor-risk patients. These four agents are considered standard of care in first-line treatment. Sorafenib, axitinib and everolimus are standard of care in second line in different settings based on their benefit in PFS. Besides some benefit described for IL-2 in highly selected patients in first line, there is a promising and emerging role for the new immunotherapeutic approaches in metastatic renal cell carcinoma.

PD-L1 expression in nonclear-cell renal cell carcinoma

BACKGROUND

Programmed death ligand-1 (PD-L1) expression in nonclear-cell RCC (non-ccRCC) and its association with clinical outcomes are unknown.

METHODS

Formalin-fixed paraffin-embedded (FFPE) specimens were obtained from 101 patients with non-ccRCC. PD-L1 expression was evaluated by immunohistochemistry in both tumor cell membrane and tumor-infiltrating mononuclear cells (TIMC). PD-L1 tumor positivity was defined as ≥5% tumor cell membrane staining. For PD-L1 expression in TIMC, a combined score based on the extent of infiltrate and percentage of positive cells was used. Baseline clinico-pathological characteristics and outcome data [time to recurrence (TTR) and overall survival (OS)] were correlated with PD-L1 staining.

RESULTS

Among 101 patients, 11 (10.9%) were considered PD-L1+ in tumor cells: 2/36 (5.6%) of chromophobe RCC, 5/50 (10%) of papillary RCC, 3/10 (30%) of Xp11.2 translocation RCC and 1/5 (20%) of collecting duct carcinoma. PD-L1 positivity (PD-L1+) in tumor cells was significantly associated with higher stage (P = 0.01) and grade (P = 0.03), as well as shorter OS (P < 0.001). On the other hand, PD-L1 positivity by TIMC was observed in 57 (56.4%) patients: 13/36 (36.1%) of chromophobe RCC, 30/50 (60%) of papillary RCC, 9/10 (90%) of Xp11.2 translocation RCC and 5/5 (100%) of collecting duct carcinoma. A trend toward shorter OS was observed in patients with PD-L1+ in TIMC (P = 0.08). PD-L1+ in both tumor cell membrane and TIMC cells were associated with shorter TTR (P = 0.02 and P = 0.03, respectively).

CONCLUSION

In non-ccRCC, patients with PD-L1+ tumors appear to have worse clinical outcomes, although only PD-L1 positivity in tumor cells is associated with higher tumor stage and grade.

MET is a potential target across all papillary renal cell carcinomas: result from a large molecular study of pRCC with CGH array and matching gene expression array

PURPOSE

Papillary renal cell carcinomas (pRCC) are the most common nonclear cell RCC subtype. Germline mutations of the MET oncogene at 7q31 have been detected in patients with hereditary type I pRCC and in 13% of sporadic type I pRCC. Recent report of MET inhibition strengthened the role of c-Met inhibition across pRCC.

EXPERIMENTAL DESIGN

We collected 220 frozen samples of sporadic pRCC through the French RCC Network and quality controlled for percentage of malignant cells >70%. Gene expression was assessed on 98 pRCC using human whole-genome Agilent 8 × 60K arrays. Copy number alterations were analyzed using Agilent Human 2 × 400K and 4× 180K array for type II pRCC and comparative genomic microarray analysis method for type I pRCC. MET gene sequencing was performed on type I pRCC.

RESULTS

MET expression level was high across all pRCC. We identified copy number alterations (gain) in 46% of type II pRCC and in 81% of type I pRCC. Correlation between DNA copy number alterations and mRNA expression level was highly significant. Eleven somatic mutations of MET gene were identified amongst 51 type I pRCC (21.6%), including 4 new mutations. We validated LRRK2 cokinase as highly correlated to MET expression.

CONCLUSION

The present report expands the role of MET activation as a potential target across all pRCC subtypes. These data support investigating MET inhibitors in pRCC in correlation with MET activation status.

Characterization of pomiferin triacetate as a novel mTOR and translation inhibitor

Deregulation of the phosphatidylinositol 3-kinase (PI3K)-Akt-mammalian target of rapamycin (mTOR)-70kDa ribosomal protein S6 kinase 1 (p70(S6K)) pathway is commonly observed in many tumors. This pathway controls proliferation, survival, and translation, and its overactivation is associated with poor prognosis for tumor-associated survival. Current efforts focus on the development of novel inhibitors of this pathway. In a cell-based high-throughput screening assay of 15,272 pure natural compounds, we identified pomiferin triacetate as a potent stabilizer of the tumor suppressor programmed cell death 4 (Pdcd4). Mechanistically, pomiferin triacetate appeared as a general inhibitor of the PI3K-Akt-mTOR-p70(S6K) cascade. Interference with this pathway occurred downstream of Akt but upstream of p70(S6K). Specifically, mTOR kinase emerged as the molecular target of pomiferin triacetate, with similar activities against mTOR complexes 1 and 2. In an in vitro mTOR kinase assay pomiferin triacetate dose-dependently inhibited mTOR with an IC50 of 6.2 μM. Molecular docking studies supported the interaction of the inhibitor with the catalytic site of mTOR. Importantly, pomiferin triacetate appeared to be highly selective for mTOR compared to a panel of 17 lipid and 50 protein kinases tested. As a consequence of the mTOR inhibition, pomiferin triacetate efficiently attenuated translation. In summary, pomiferin triacetate emerged as a novel and highly specific mTOR inhibitor with strong translation inhibitory effects. Thus, it might be an interesting lead structure for the development of mTOR- and translation-targeted anti-tumor therapies.