Differential expression analysis identifies a prognostically significant extracellular matrix-enriched gene signature in hyaluronan-positive clear cell renal cell carcinoma.

Hyaluronan (HA) accumulation in clear cell renal cell carcinoma (ccRCC) is associated with poor prognosis; however, its biology and role in tumorigenesis are unknown. RNA sequencing of 48 HA-positive and 48 HA-negative formalin-fixed paraffin-embedded (FFPE) samples was performed to identify differentially expressed genes (DEG). The DEGs were subjected to pathway and gene enrichment analyses. The Cancer Genome Atlas Kidney Renal Clear Cell Carcinoma (TCGA-KIRC) data and DEGs were used for the cluster analysis. In total, 129 DEGs were identified. HA-positive tumors exhibited enhanced expression of genes related to extracellular matrix (ECM) organization and ECM receptor interaction pathways. Gene set enrichment analysis showed that epithelial-mesenchymal transition-associated genes were highly enriched in the HA-positive phenotype. A protein-protein interaction network was constructed, and 17 hub genes were discovered. Heatmap analysis of TCGA-KIRC data identified two prognostic clusters corresponding to HA-positive and HA-negative phenotypes. These clusters were used to verify the expression levels and conduct survival analysis of the hub genes, 11 of which were linked to poor prognosis. These findings enhance our understanding of hyaluronan in ccRCC.

CircPRELID2 functions as a promoter of renal cell carcinoma through the miR-22-3p/ETV1 cascade.

BACKGROUND: Emerging evidence has indicated that a number of circular RNAs (circRNAs) participate in renal cell carcinoma (RCC) carcinogenesis. Nevertheless, the activity and molecular process of circPRELID2 (hsa_circ_0006528) in RCC progression remain unknown. METHODS: CircPRELID2, miR-22-3p and ETS variant 1 (ETV1) levels were gauged by qRT-PCR. Effect of the circPRELID2/miR-22-3p/ETV1 axis was evaluated by detecting cell growth, motility, and invasion. Immunoblotting assessed related protein levels. The relationships of circPRELID2/miR-22-3p and miR-22-3p/ETV1 were confirmed by RNA immunoprecipitation (RIP), luciferase reporter or RNA pull-down assay. RESULTS: CircPRELID2 was up-regulated in RCC. CircPRELID2 silencing suppressed RCC cell growth, motility and invasion. Moreover, circPRELID2 silencing weakened M2-type macrophage polarization in THP1-induced macrophage cells. CircPRELID2 sequestered miR-22-3p, and circPRELID2 increased ETV1 expression through miR-22-3p. Moreover, the inhibitory impact of circPRELID2 silencing on RCC cell malignant behaviors was mediated by the miR-22-3p/ETV1 axis. Furthermore, circPRELID2 knockdown in vivo hampered growth of xenograft tumors. CONCLUSION: Our study demonstrates that circPRELID2 silencing can mitigate RCC malignant development through the circPRELID2/miR-22-3p/ETV1 axis, highlighting new therapeutic targets for RCC treatment.

A rare case of TFEB/6p21/VEGFA-amplified renal cell carcinoma diagnosed by whole-exome sequencing: clinicopathological and genetic feature report and literature review.

BACKGROUND: TFEB/6p21/VEGFA-amplified renal cell carcinoma (RCC) is rare and difficult to diagnose, with diverse histological patterns and immunohistochemical and poorly defined molecular genetic characteristics. CASE PRESENTATION: We report a case of a 63-year-old male admitted in 2017 with complex histomorphology, three morphological features of clear cell, eosinophilic and papillary RCC and resembling areas of glomerular and tubular formation. The immunophenotype also showed a mixture of CD10 and P504s. RCC with a high suspicion of collision tumors was indicated according to the 2014 WHO classification system; no precise diagnosis was possible. The patient was diagnosed at a different hospital with poorly differentiated lung squamous cell carcinoma one year after RCC surgery. We exploited molecular technology advances to retrospectively investigate the patient's molecular genetic alterations by whole-exome sequencing. The results revealed a 6p21 amplification in VEGFA and TFEB gene acquisition absent in other RCC subtypes. Clear cell, papillary, chromophobe, TFE3-translocation, eosinophilic solid and cystic RCC were excluded. Strong TFEB and Melan-A protein positivity prompted rediagnosis as TFEB/6p21/VEGFA-amplified RCC as per 2022 WHO classification. TMB-L (low tumor mutational load), CCND3 gene acquisition and MRE11A and ATM gene deletion mutations indicated sensitivity to PD-1/PD-L1 inhibitor combinations and the FDA-approved targeted agents Niraparib (Grade C), Olaparib (Grade C), Rucaparib (Grade C) and Talazoparib (Class C). GO (Gene Ontology) and KEGG enrichment analyses revealed major mutations and abnormal CNVs in genes involved in biological processes such as the TGF-ß, Hippo, E-cadherin, lysosomal biogenesis and autophagy signaling pathways, biofilm synthesis cell adhesion substance metabolism regulation and others. We compared TFEB/6p21/VEGFA-amplified with TFEB-translocated RCC; significant differences in disease onset age, histological patterns, pathological stages, clinical prognoses, and genetic characteristics were revealed. CONCLUSION: We clarified the patient's challenging diagnosis and discussed the clinicopathology, immunophenotype, differential diagnosis, and molecular genetic information regarding TFEB/6p21/VEGFA-amplified RCC via exome analysis and a literature review.

Molecular and functional characterization of reversible-sunitinib-tolerance state in human renal cell carcinoma.

Therapy failure with the tyrosine kinase inhibitor (TKI) sunitinib remains a great challenge in metastatic renal cell carcinoma (mRCC). Growing evidence indicates that the tumour subpopulation can enter a transient, non-mutagenic drug-tolerant state to endure the treatment underlying the minimal residual disease and tumour relapse. Drug tolerance to sunitinib remains largely unexplored in RCC. Here, we show that sunitinib-tolerant 786-O/S and Caki-2/S cells are induced by prolonged drug treatment showing reduced drug sensitivity, enhanced clonogenicity, and DNA synthesis. Sunitinib-tolerance developed via dynamic processes, including (i) engagement of c-MET and AXL pathways, (ii) alteration of stress-induced p38 kinase and pro-survival BCL-2 signalling, (iii) extensive actin remodelling, which was correlated with activation of focal adhesion proteins. Remarkably, the acute drug response in both sensitive and sunitinib-tolerant cell lines led to dramatic fine-tuning of the actin-cytoskeleton and boosted cellular migration and invasion, indicating that the drug-response might depend on cell state transition rather than pre-existing mutations. The drug-tolerant state was transiently acquired, as the cells resumed initial drug sensitivity after >10 passages under drug withdrawal, reinforcing the concept of dynamic regulation and phenotypic heterogeneity. Our study described molecular events contributing to the reversible switch into sunitinib-tolerance, providing possible novel therapeutic opportunities in RCC.

Acetylation- and ubiquitination-regulated SFMBT2 acts as a tumor suppressor in clear cell renal cell carcinoma.

BACKGROUND: Clear cell renal cell carcinoma (RCC) is the most common kidney tumor. The analysis from medical database showed that Scm-like with four MBT domains protein 2 (SFMBT2) was decreased in advanced clear cell RCC cases, and its downregulation was associated with the poor prognosis. This study aims to investigate the role of SFMBT2 in clear cell RCC. METHODS: The expression of SFMBT2 in clear cell RCC specimens were determined by immunohistochemistry staining and western blot. The overexpression and knockdown of SFMBT2 was realized by infection of lentivirus loaded with SFMBT2 coding sequence or silencing fragment in 786-O and 769-P cells, and its effects on proliferation and metastasis were assessed by MTT, colony formation, flow cytometry, wound healing, transwell assay, xenograft and metastasis experiments in nude mice. The interaction of SFMBT2 with histone deacetylase 3 (HDAC3) and seven in absentia homolog 1 (SIAH1) was confirmed by co-immunoprecipitation. RESULTS: In our study, SFMBT2 exhibited lower expression in clear cell RCC specimens with advanced stages than those with early stages. Overexpression of SFMBT2 inhibited the growth and metastasis of clear cell RCC cells, 786-O and 769-P, in vitro and in vivo, and its silencing displayed opposites effects. HDAC3 led to deacetylation of SFMBT2, and the HDAC3 inhibitor-induced acetylation prevented SFMBT2 from SIAH1-mediated ubiquitination modification and proteasome degradation. K687 in SFMBT2 protein molecule may be the key site for acetylation and ubiquitination. CONCLUSIONS: SFMBT2 exerted an anti-tumor role in clear cell RCC cells, and HDAC3-mediated deacetylation promoted SIAH1-controlled ubiquitination of SFMBT2. SFMBT2 may be considered as a novel clinical diagnostic marker and/or therapeutic target of clear cell RCC, and crosstalk between its post-translational modifications may provide novel insights for agent development.

Comparison of different 2D muscle indexes measured at the level of the 3rd lumbar vertebra in survival prediction in patients with renal cell carcinoma.

BACKGROUND: Low computed tomography (CT)-determined muscle mass, commonly determined with height-adjusted muscle indexes (MIs), predicts worse survival in several cancers and has been suggested as a prognostic assessment tool. Although several MIs measured at the level of the 3rd lumbar vertebra (L3) are commonly used, it remains unestablished how different L3-determined MIs perform in survival prognostication compared to each other. The objective of this study was to investigate the performance of different MIs for survival prognostication in renal cell carcinoma (RCC). METHODS: We retrospectively enrolled 214 consecutive patients with RCC. We determined three L3-MIs (psoas muscle index (PMI), psoas muscle index and erector spinae index (PMI+ESI), and whole skeletal muscle index (SMI)) from preoperative CT scans. Categorization of those with low and normal muscle mass was based on the Youden Index sex-specific MI cut-offs. We determined sensitivity, specificity, and accuracy metrics for predicting 1-year, 5-year, and overall survival (OS) using Cox regression models. RESULTS: Low PMI, PMI+ESI, and SMI significantly predicted decreased 1-year, 5-year, and OS in uni- and multivariate models. PMI+ESI and SMI were more accurate than PMI in males, and PMI and PMI+ESI were more accurate than SMI in females in the prediction of 1-year survival. However, there were no differences in accuracies between MIs in 5-year and OS prediction. INTERPRETATION: PMI+ESI performed well overall in short-term prognostication, but there were no differences between the MIs in long-term prognostication. We recommend the use of PMI+ESI for muscle evaluation, particularly when SMI cannot be evaluated.

End-stage renal disease after renal cancer surgery: risk factors and overall survival.

OBJECTIVE: Several risk factors for end-stage renal disease (ESRD), in patients undergoing surgical treatment for renal cell carcinoma (RCC), have been suggested by others. This study aimed to investigate such risk factors and disclose the effect of developing ESRD, postoperatively, on overall survival. The risk of developing ESRD after RCC diagnosis was also evaluated. MATERIAL AND METHODS: The data of 16,220 patients with RCC and 162,199 controls were extracted from the Renal Cell Cancer Database Sweden, with linkages across multiple national registers between 2005 and 2020. Cox proportional hazards regression, Kaplan-Meier curves and cumulative incidence were used for statistical analysis. RESULTS: The 5-year cumulative incidence of ESRD following RCC diagnosis was 2.4% (95% confidence interval [CI] 2.1-2.6) and 0.4% (95% CI 0.3-0.4) for the patients with RCC and controls, respectively. Age, chronic kidney disease, higher T-stage and radical nephrectomy (RN) were significant risk factors for ESRD within 1-year of surgery. A total of 104 and 12,152 patients with and without ESRD, respectively, survived 1-year postoperatively. The 5-year overall survival rates of patients with ESRD and those with RCC only were 50% (95% CI 0.40-0.60) and 80% (95% CI 0.80-0.81), respectively. CONCLUSIONS: Patients who developed ESRD following renal cancer surgery had significantly poorer survival outcomes. Advanced age, comorbidities, higher-stage tumours and RN were identified as risk factors for developing ESRD. Surgical decisions are crucial. Efforts to spare renal function, including nephron-sparing surgery and active surveillance in appropriate cases, are highly relevant to reduce the development of severe kidney dysfunction.

Robot-assisted partial nephrectomy in younger versus older adults with renal cell carcinoma: a propensity score-matched analysis.

PURPOSE: Our study aimed to compare the surgical outcomes of robot-assisted partial nephrectomy (RAPN) between younger and older patients after adjusting for their background differences. We particularly assessed RAPN outcomes and safety in older patients. METHODS: We retrospectively evaluated 559 patients clinically diagnosed with T1 renal cell carcinoma (RCC) and treated with RAPN between 2013 and 2022 at five institutions in Japan. The patients were classified into two groups according to their age during surgery (younger group: < 75 years, older group: ≥ 75 years). Propensity score matching (PSM) was performed to adjust for the differences in the backgrounds between younger and older patients, and surgical outcomes were compared. RESULTS: Among the 559 patients, 422 (75.5%) and 137 (24.5%) were classified into the younger and older groups, respectively; 204 and 102 patients from the younger and older groups were matched according to PSM, respectively. Subsequently, patient characteristics other than age were not significantly different between the two groups. In the matched cohort, the older group had more patients with major complications (younger, 3.0%; older, 8.8%; P = 0.045). CONCLUSION: Surgical outcomes of RAPN in older patients with RCC were comparable with those in younger patients, although older patients experiencedsignificantly more complications than younger patients. These results suggest the need for further detailed preoperative evaluation and appropriate postoperative management in older patients receiving RAPN.

Minimally invasive transperitoneal partial versus radical nephrectomy in obese patients: perioperative and long-term functional outcomes from a large perspective contemporary series (RECORd2 project).

BACKGROUND: The aim of this study is to evaluate the perioperative and long-term functional outcomes of laparoscopic (LPN) and robot-assisted partial nephrectomy (RAPN) in comparison to laparoscopic radical nephrectomy (LRN) in obese patients diagnosed with renal cell carcinoma. METHODS: Clinical data of 4325 consecutive patients from The Italian REgistry of COnservative and Radical Surgery for cortical renal tumor Disease (RECORD 2 Project) were gathered. Only patients treated with transperitoneal LPN, RAPN, or LRN with Body Mass Index (BMI) ≥30 kg/m2, clinical T1 renal tumor and preoperative estimated glomerular filtration rate (eGFR) ≥60 mL/min, were included. Perioperative, and long-term functional outcomes were examined. RESULTS: Overall, 388 patients were included, of these 123 (31.7%), 120 (30.9%) and 145 (37.4%) patients were treated with LRN, LPN, and RAPN, respectively. No significant difference was observed in preoperative characteristics. Overall, intra and postoperative complication rates were comparable among the groups. The LRN group had a significantly increased occurrence of acute kidney injury (AKI) compared to LPN and RAPN (40.6% vs. 15.3% vs. 7.6%, P=0.001). Laparoscopic RN showed a statistically significant higher renal function decline at 60-month follow-up assessment compared to LPN and RAPN. A significant renal function loss was recorded in 30.1% of patients treated with LRN compared to 16.7% and 10.3% of patients treated with LPN and RAPN (P=0.01). CONCLUSIONS: In obese patients, both LPN and RAPN showcased comparable complication rates and higher renal function preservation than LRN. These findings highlighted the potential benefits of minimally invasive PN over radical surgery in the context of obese individuals.

SPP1 expression indicates outcome of immunotherapy plus tyrosine kinase inhibition in advanced renal cell carcinoma.

Clinical guidelines have recently advised combination therapy involving immunotherapy (IO) and tyrosine kinase inhibitors (TKI) as the first-line therapy approach for advanced renal cell carcinoma (RCC). Nevertheless, there is currently no available biomarker that can effectively distinguish the progression-free survival (PFS). RNA-sequencing and immunohistochemistry were conducted on our cohort of metastatic RCC patients, namely ZS-MRCC, who received combination therapy consisting of IO and TKI. We further applied RNA-sequencing, immunohistochemistry, and flow cytometry to examine the immune cell infiltration and functionality inside the tumor microenvironment of high-risk localized RCC samples. SPP1 expression was significantly higher in non-responders to IO-TKI therapy. Elevated levels of SPP1 were associated with poor PFS in both the ZS-MRCC cohort (HR = 2.73, p = .018) and validated in the JAVELIN Renal 101 cohort (HR = 1.61, p = .004). By multivariate Cox analysis, SPP1 was identified as a significant independent prognosticator. Furthermore, there existed a negative correlation between elevated levels of SPP1 and the presence of GZMB+CD8+ T cells (Spearman's ρ= -0.48, p < .001). Conversely, SPP1 expression is associated with T cell exhaustion markers. A significant increase in the abundance of Tregs was observed in tumors with high levels of SPP1. Additionally, a machine-learning-based model was constructed to predict the benefit of IO-TKI treatment. High SPP1 is associated with therapeutic resistance and unfavorable PFS in IO-TKI therapy. SPP1 expression have also been observed to be indicative of malfunction and exhaustion in T cells. Increased SPP1 expression has the potential to serve as a potential biomarker for treatment selection of metastatic RCC.

Predictors of renal function deterioration at one year after off-clamp non-renorrhaphy partial nephrectomy.

BACKGROUND: Preservation of renal function is an important goal in renal cell carcinoma-related surgery. Although several case-dependent techniques for renal pedicle clamping and hemostasis have been used, their effects on long-term renal function are controversial. METHODS: The clinical records of 114 patients who underwent off-clamp non-renorrhaphy open partial nephrectomy at our hospital were retrospectively reviewed. Perioperative estimated glomerular filtration rate (eGFR) preservation was calculated, and predictors of eGFR decline 12 months post-surgery and overtime deterioration of renal function were identified using a multivariate regression analysis. RESULTS: The median patient age was 65 years, and the median tumor size was 27 mm. The mean eGFR preservation at 1, 3, and 12 months post-surgery were 90.1%, 89.0%, and 86.9%, respectively. eGFR decline at 1 and 3 months were associated with poor eGFR preservation at 12 months with the odds ratio (95% confidence interval (CI)) of 1.97 and 3.157, respectively. Multivariate regression analyses revealed that tumor size was an independent predictor of eGFR decline at 12 months. Among 65 patients with eGFR preservation over 90% at 1 month post-surgery, eGFR value of 28 patients deteriorated below 90% at 12 months post-surgery compared with preoperative eGFR. Tumor size and eGFR preservation at 1 month were independent predictors of long-term renal function deterioration. CONCLUSION: Tumor size predicted eGFR decline 12 months post-surgery. Only a mild decline in eGFR was observed between 3 and 12 months after open partial nephrectomy. Tumor size and eGFR preservation at 1 month predicted the deterioration of renal function over time.

Tumor microenvironment and clinical efficacy of first line immunotherapy-based combinations in metastatic renal cell carcinoma.

The impact of tumor microenvironment (TME) in influencing clinical response to first-line immune checkpoint inhibitor (ICI)-based treatment in advanced renal cell carcinoma (RCC) is unclear. Immunohistochemistry (IHC) could identify biomarkers related to immune checkpoints and immune cell population. This study retrospectively characterized TME from 28 RCC patients who received first line ICI-based therapy through IHC assessment of selected markers and explored preliminary evidence about their possible correlation with treatment efficacy. We found a significantly higher count of CD80+, CD163+ cells and their ratio in RCC with clear cell component compared to those without clear cell features; additionally, patients with metastatic disease at diagnosis were associated with higher expression of CD163+ cells, while higher count of CD4+ cells and CD4+/CD8+ ratio were found in RCC with sarcomatoid features. Patients achieving partial or complete response were associated with lower expression of CD163+ cells (median 28 vs 47; p = 0.049). Furthermore, lower expression of CD163+ was associated with better PFS (median PFS 20.0 vs 4.7 months; HR 0.22 p = 0.011) and OS (median OS NR vs 14.4 months; HR 0.28 p = 0.036). A longer OS was reported in PD-L1 CPS negative patients (median OS NR vs 11.8 months; HR 0.20 p = 0.024). High infiltration of CD163+ macrophages, who typically present "anti-inflammatory" M2-like phenotype, could identify a subgroup of patients with poor survival after receiving first-line ICI.

A Cerebellar Tumor-to-Tumor Metastasis in a Patient With Von Hippel-Lindau Disease.

Tumor-to-tumor metastasis in the central nerve system is uncommon in our routine practice. Most reports include metastatic breast cancer into meningioma. Here we report a metastatic clear cell renal cell carcinoma (ccRCC) into a cerebellar hemangioblastoma in a patient with von Hippel-Lindau (VHL) disease. Imaging cannot distinguish metastatic ccRCC from primary cerebellar hemangioblastoma. Immuno-molecular studies are proven to be diagnostic. We also reviewed previously documented tumor-to-tumor metastasis of ccRCC to cerebellar hemangioblastoma in VHL disease. Lastly, we discussed potential mechanisms involved in the metastasis of ccRCC to hemangioblastoma in the cerebellum in patients with VHL.

CXCR2/Snail-1-Induced Epithelial-Mesenchymal Transition in the Formation and Progression of RCC with Inferior Vena Cava Tumour Thrombus.

BACKGROUND: Renal cell carcinoma (RCC), a common and highly invasive malignant tumour, presents clinical challenges due to its propensity for easy metastasis. Inferior vena cava tumour thrombus is a common RCC complication significantly impacting patient prognosis. This study investigates C-X-C chemokine receptor type 2 (CXCR2)/Snail-1-induced epithelial-mesenchymal transition (EMT) in RCC with inferior vena cava tumour thrombus. METHODS: Tissues from 51 RCC patients were analysed for CXCR2 and Snail-1 Messenger Ribonucleic Acid (mRNA) levels using Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR). Elevated levels of both were observed in tumour and inferior vena cava tumour thrombus tissues. Using Short Hairpin RNA (shRNA) technology, we inhibited CXCR2 and Snail-1 expression to investigate their impact on EMT, invasiveness, and metastatic potential in RCC cells. RESULTS: Compared with that in the Short Hairpin RNA-Negative Control (ShNC) group, inhibition of CXCR2 and Snail-1 suppressed the degree of EMT, invasiveness, and metastatic ability of RCC cells (p < 0.01). Further mechanistic studies showed that CXCR2/Snail-1 participated in the formation and progression of RCC by regulating the extracellular signal-regulated kinase 1/2 (ERK1/2) signalling pathways. Additionally, compared with that in the ShNC group, knockdown of CXCR2 and Snail-1 significantly inhibited the expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9; p < 0.01), thereby regulating the metastasis of RCC. CONCLUSIONS: Our findings suggest that CXCR2/Snail-1-induced EMT plays an important role in the formation and progression of RCC with inferior vena cava tumour thrombus. CXCR2/Snail-1 participates in the invasion and metastasis of RCC by regulating the expression of multiple signalling pathways and related genes. These results provide new insights and directions for the treatment of RCC.

Therapeutic Drug Monitoring of Pazopanib in Renal Cell Carcinoma and Soft Tissue Sarcoma: A Systematic Review.

BACKGROUND: Pazopanib, an anti-angiogenic multitarget tyrosine kinase inhibitor, has been approved for the treatment of metastatic renal cell carcinoma and soft tissue sarcoma. However, its recommended dose does not always produce consistent outcomes, with some patients experiencing adverse effects or toxicity. This variability is due to differences in the systemic exposure to pazopanib. This review aimed to establish whether sufficient evidence exists for the routine or selective therapeutic drug monitoring of pazopanib in adult patients with approved indications. METHODS: A systematic search of the PubMed and Web of Science databases using search terms related to pazopanib and therapeutic drug monitoring yielded 186 and 275 articles, respectively. Ten articles associated with treatment outcomes or toxicity due to drug exposure were selected for review. RESULTS: The included studies were evaluated to determine the significance of the relationship between drug exposure/Ctrough and treatment outcomes and between drug exposure and toxicity. A relationship between exposure and treatment outcomes was observed in 5 studies, whereas the trend was nonsignificant in 4 studies. A relationship between exposure and toxicity was observed in 6 studies, whereas 2 studies did not find a significant relationship; significance was not reported in 3 studies. CONCLUSIONS: Sufficient evidence supports the therapeutic drug monitoring of pazopanib in adult patients to improve its efficacy and/or safety in the approved indications.

Clinical and pathological characteristics of renal cell carcinomas with MiTF translocation.

INTRODUCTION: Microphthalmia Transfactor Family (MiTF) translocation renal cell carcinomas (RCCs) represent a rare subtype of renal cell cancers. They are diagnosed in young patients and have a poor prognosis. The aim of our study was to analyze the clinical and pathological features of patients with MiTF RCC. MATERIAL AND METHOD: We performed a retrospective, monocentric, descriptive study including all patients operated for RCC between January 2015 and January 2023. The diagnosis of MiTF RCC was suspected by immunohistochemistry (IHC) and confirmed by fluorescent in situ hybridization (FISH). Survival data according to histological subtype (MiTF versus ccRCC) were analyzed using the Kaplan-Meier method and compared using a log-rank test. The primary endpoint was recurrence-free survival (RFS). A descriptive cohort analysis was performed. RESULTS: Of the 960 patients included, 19 (2%) had FISH-confirmed MiTF tumors. The median age at diagnosis was 42 years [18-75], the sex ratio was 1.11 females for 1 male, and 4 (21%) patients were immediately metastatic. Median RFS was 21months for patients in the MiTF group and was significantly lower than that of ccRCC patients, HR=4.33 [CI95% 2.06; 9.10; P<0.001]. Of the 11 patients with cT1-T2 tumors, 9 (81.8%) were treated with nephron sparing-surgery, with 2 (22.2%) harbored local recurrence. CONCLUSION: Our study shows that patients with MiTF translocation RCC have a significantly lower RFS than non-MiTF RCC patients. Nephron sparing surgery must be weighted by the high risk of recurrence in this particularly young population.