Purpose: Recurrent renal cell carcinoma(reRCC) is associated with poor prognosis and the underlying mechanism is not yet clear. A comprehensive understanding of tumor microenvironment (TME) of reRCC may aid in designing effective anticancer therapies, including immunotherapies. Single-cell transcriptomics holds great promise for investigating the TME, however, this technique has not been used in reRCC. Here, we aimed to explore the difference in the TME and gene expression pattern between primary RCC (pRCC) and reRCC at single-cell level. Experimental design: We performed single-cell RNA sequencing analyses of 32,073 cells from 2 pRCC, 2 reRCC, and 3 adjacent normal kidney samples. 41 pairs of pRCC and reRCC samples were collected as a validation cohort to assess differences observed in single-cell sequencing. The prognostic significance of related cells and markers were studied in 47 RCC patients underwent immunotherapy. The function of related cells and markers were validated via in vitro and in vivo experiments. Results: reRCC had reduced CD8⁺ T cells but increased cancer-associated fibroblasts (CAFs) infiltration compared with pRCC. Reduced CD8⁺ T cells and increased CAFs infiltration were significantly associated with a worse response from immunotherapy. Remarkably, CAFs showed substantial expression of LGALS1 (Gal1). In vitro, CAFs could induce CD8⁺ T cells apoptosis via Gal1. In vivo, knockdown of Gal1 in CAFs suppressed tumor growth, increased CD8⁺ T cells infiltration, reduced the proportion of apoptotic CD8⁺ T cells and enhanced the efficacy of immunotherapy. Conclusions: We delineated the heterogeneity of reRCC and highlighted an innovative mechanism that CAFs acted as a suppressor of CD8⁺ T cells via Gal1. Targeting Gal1 combined with anti-PD1 showed promising efficacy in treating RCC.

Clinically, patients with urothelial carcinoma of the bladder (UCB) with tumor metastasis are incurable. To find new therapeutic strategies, the mechanisms underlying UCB invasion and metastasis should be further investigated. In this study, zinc finger and homeobox 3 (ZHX3) was first screened as a critical oncogenic factor associated with poor prognosis in a UCB dataset from The Cancer Genome Atlas (TCGA). These results were also confirmed in a large cohort of clinical UCB clinical samples. Next, we found that ZHX3 could promote the migration and invasion capacities of UCB cells both in vitro and in vivo. Mechanistically, coimmunoprecipitation (coIP) and mass spectrometry (MS) analysis indicated that ZHX3 was a target of tripartite motif 21 (TRIM21), which mediates its ubiquitination, and subsequent degradation. Notably, RNA‐seq analysis showed that ZHX3 repressed the expression of regulator of G protein signaling 2 (RGS2). Generally, our results suggest that ZHX3 plays an oncogenic role in UCB pathogenesis and might serve as a novel therapeutic target for UCB.

Purpose: Fumarate hydratase–deficient renal cell carcinoma (FHRCC) is highly malignant, but the urgent need for effective treatment remains unmet. We aimed to analyze the genomic characteristics and microenvironment of FHRCC and the cause of heterogeneous response to immune checkpoint inhibitor (ICI)-based treatment at single-cell level. Experimental Design: Whole-exome sequencing and IHC staining analyses were performed in 30 advanced FHRCC patients. Single-cell RNA sequencing following ICI-based treatment was conducted in 4 patients. The clinical characteristics, therapeutic effect, and follow-up data were analyzed. Results: The median tumor mutation burden was only 0.14 mutations per megabase. IHC staining showed an immune-active tumor microenvironment characterized by extensive CD8+ T-cell infiltration. ATM expression was inversely correlated with percentage of tumor-infiltrating CD8+ T cells. Trajectory analysis indicated gradually upregulated exhausted markers and an increased apoptotic trend of CD8+ T cells despite continuous exposure to ICI-based treatment. ICI-based treatment was associated with improved overall response rate (17.6% vs. 0%, P = 0.046) and disease control rate (DCR; 64.7% vs. 12.5%, P = 0.004) compared with tyrosine kinase inhibitor. Among patients with germline mutation, the ORR (16.7% vs. 0%, P = 0.086) and the DCR (66.7% vs. 14.3%, P = 0.011) were higher after ICI-based treatment. Conclusions: Immune infiltration is frequent in FHRCC. ICI-based treatment is a promising regimen, and treatment response depends on the functional status of tumor-infiltrating lymphocytes. ICI-based treatment cannot reverse the exhaustion of CD8+ T cells in patients with progressive disease, highlighting the need for additional therapeutic strategies.

Although high body mass index (BMI) was reported to associate with a better prognosis for metastatic renal cell cancer (mRCC) patients receiving anti-vascular endothelial growth factor (anti-VEGF) therapy, it is an imperfect proxy for the body composition, especially in Asian patients with a lower BMI. The role of visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and perirenal fat thickness (PRFT) in mRCC patients was still unknown. Therefore, a multicenter retrospective study of 358 Chinese mRCC patients receiving anti-VEGF therapy was conducted and their body composition was measured via computed tomography. We parameterized VAT, SAT and PRFT according to their median value and BMI according to Chinese criteria (overweight: BMI ≥ 24). We found VAT, SAT, and PRFT (all p < 0.05) but not BMI, significantly associated with overall survival (OS) and progression-free survival (PFS). Multivariate Cox analysis identified PRFT was the independent predictor of OS and PFS, and IMDC expanded with PRFT showed the highest C-index in predicting OS (OS:0.71) compared with VAT, SAT, and BMI. PRFT could increase the area under the curve of the traditional International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) model in OS (70.54% increase to 74.71%) and PFS (72.22% increase to 75.03%). PRFT was introduced to improve the IMDC model and PRFT-modified IMDC demonstrated higher AIC in predicting OS and PFS compared with the traditional IMDC model. Gene sequencing analysis (n = 6) revealed that patients with high PRFT had increased angiogenesis gene signatures (NES = 1.46, p = 0.04) which might explain why better drug response to anti-VEGF therapy in mRCC patients with high PRFT. The main limitation is retrospective design. This study suggests body composition, especially PRFT, is significantly associated with prognosis in Chinese mRCC patients receiving anti-VEGF therapy. PRFT-modified IMDC model proposed in this study has better clinical predictive value.

Background: The ipsilateral renal parenchymal volume (RPV) experiences a sharp decrease shortly after partial nephrectomy (PN), mainly due to surgical remove or devascularization of kidney tissue. However, the subsequent change of RPV and its association with glomerular filtration rate (GFR) fast decline remains unknown. Our objective was to investigate the change of ipsilateral RPV and renal function status from new baseline (1–12 months after PN) to latest follow-up (≥1 year) after PN, and to explore factors associated with ipsilateral RPV decrease rate and correlation between RPV decrease and GFR fast decline. Materials and methods: A retrospective review of 367 patients with PN was conducted. Three-dimensional reconstruction of computed tomography (CT)/MRI images was performed for RPV calculation. Spectrum score was used to assess the degree of acute kidney injury (AKI) in the operated kidney after PN. GFR decline greater than 3 ml/min/1.73 m²/year was defined as GFR fast decline. One hundred fourteen patients underwent abdominal surgery was used as control. Predictive factors for subsequent decrease of RPV rate and GFR fast decline were evaluated by linear and logistic regression, respectively. Results: With a median interval time of 21.1 (interquartile range:13.8–35.5) months, median ipsilateral RPV significantly decreased from 118.7 (interquartile range:100.7–137.1) ml at new baseline to 111.8 (IQR: 92.3–131.3) ml at latest follow-up. The interval time [β: 1.36(0.71–2.01), P<0.001] and spectrum score [β: 5.83 (2.92–8.74), P<0.001] were identified as independent predictors of ipsilateral RPV decrease rate. GFR fast decline was observed in 101 (27.5%) patients. Annual ipsilateral RPV decrease rate [odds ratio:1.67 (1.05–2.67), P=0.03] and overweight [odds ratio:1.63 (1.02–2.60), P=0.04] were independent predictors of GFR fast decline. Conclusions: Ipsilateral RPV experienced a moderate but significant decrease during follow-up after PN, especially in those with severer acute kidney injury. The presence of GFR fast decline was found to be associated with reduction of ipsilateral RPV, particularly in overweight individuals.

Sunitinib is one of the first-line targeted drugs for metastatic renal cell carcinoma (RCC) with dual effects of antiangiogensis and proapoptosis. Sam68 (Src-associated in mitosis, 68 KDa), is found being involved in cell apoptosis. This article reveals that Sam68 impacts the sensitivity to sunitinib by mediating the apoptosis of RCC cells. Immunohistochemical staining indicated that the Sam68 expression levels in sunitinib sensitive tumor tissues were markedly higher than those in sunitinib resistant tumor tissues. Sunitinib induced RCC cell apoptosis in a concentration-dependent manner and inhibited the expression of total and phosphorylated Sam68 (p-Sam68). Downregulation of Sam68 expression inhibited RCC cell apoptosis induced by sunitinib. While upregulation of Sam68 expression could enhance apoptosis induced by sunitinib. Xenograft models showed that tumors in the Sam68-knockdown group did not shrink as much as those in the control group after treatment with sunitinib for 4 weeks. Together, our results suggest that Sam68 expression is associated with the sensitivity of ccRCC patients to sunitinib. Sam68 may promote cell apoptosis induced by sunitinib, and the Sam68 expression level may be a biomarker for predicting sunitinib sensitivity in ccRCC patients.