IDH2 stabilizes HIF-1α-induced metabolic reprogramming and promotes chemoresistance in urothelial cancer.

Drug resistance contributes to poor therapeutic response in urothelial carcinoma (UC). Metabolomic analysis suggested metabolic reprogramming in gemcitabine-resistant urothelial carcinoma cells, whereby increased aerobic glycolysis and metabolic stimulation of the pentose phosphate pathway (PPP) promoted pyrimidine biosynthesis to increase the production of the gemcitabine competitor deoxycytidine triphosphate (dCTP) that diminishes its therapeutic effect. Furthermore, we observed that gain-of-function of isocitrate dehydrogenase 2 (IDH2) induced reductive glutamine metabolism to stabilize Hif-1α expression and consequently stimulate aerobic glycolysis and PPP bypass in gemcitabine-resistant UC cells. Interestingly, IDH2-mediated metabolic reprogramming also caused cross resistance to CDDP, by elevating the antioxidant defense via increased NADPH and glutathione production. Downregulation or pharmacological suppression of IDH2 restored chemosensitivity. Since the expression of key metabolic enzymes, such as TIGAR, TKT, and CTPS1, were affected by IDH2-mediated metabolic reprogramming and related to poor prognosis in patients, IDH2 might become a new therapeutic target for restoring chemosensitivity in chemo-resistant urothelial carcinoma.

Vasohibin-1 Expression Can Predict Pathological Complete Remission of Advanced Bladder Cancer with Neoadjuvant Chemotherapy.

BACKGROUND AND PURPOSE: Neoadjuvant chemotherapy (NAC) is a well-established standard practice in invasive bladder cancer (BCa), however patient selection remains challenging. High expression of vasohibin-1 (VASH1), an endogenous regulator of angiogenesis, has been reported in high-grade and advanced BCa; however, its prognostic value for chemotherapy outcomes remains unexplored. In this study, we sought to identify biomarkers of chemotherapy response focusing on the relationship between angiogenesis and tissue hypoxia. METHODS: Forty Japanese patients with BCa who underwent NAC and radical cystectomy were included in the present analysis. We compared the immunohistochemical expression of CD34, VASH1, and carbonic anhydrase 9 (CA9) between patients who achieved tumor clearance at operation (ypT0) and those with residual disease after cystectomy. RESULTS: There were 19 patients in the ypT0 group, while the remaining 21 patients had residual tumors at operation. Patients in the ypT0 group had high microvessel density (p = 0.031), high VASH1 density (p < 0.001), and stronger CA9 staining (p = 0.046) than their counterparts. Multivariate analysis identified microvessel and VASH1 density as independent predictive factors for pathological ypT0 disease (p = 0.043 and 0.002, respectively). The 5-year recurrence-free survival rate was higher in the high VASH1 density group than in the low VASH1 density group (66.3% vs. 33.3%, p = 0.036). CONCLUSION: VASH1 density is a potential therapeutic biomarker for chemotherapy response in BCa.

Prediction of pathological up-staging after radical nephroureterectomy in patients with upper tract urothelial carcinoma.

PURPOSE: The diagnostic accuracy of computed tomography urography for upper tract urothelial carcinoma is high; however, difficulties are associated with precisely assessing the T stage. Preoperative tumor staging has an impact on treatment options for upper tract urothelial carcinoma. We herein attempted to identify preoperative factors that predict pathological tumor up-staging, which will facilitate the selection of treatment strategies. MATERIALS AND METHODS: We retrospectively identified 148 patients with upper tract urothelial carcinoma who underwent computed tomography urography preoperatively followed by radical nephroureterectomy without preoperative chemotherapy at our institution between 2000 and 2021. Preoperative factors associated with cT2 or lower to pT3 up-staging were examined using a multivariate logistic regression analysis. RESULTS: Ninety out of 148 patients were diagnosed with cT2 or lower, and 22 (24%) were up-staged to pT3. A multivariate analysis identified a positive voided urine cytology (HR 4.69, p = 0.023) and tumor length ≥ 3 cm (HR 6.33, p = 0.003) as independent predictors of pathological tumor up-staging. CONCLUSIONS: Patients diagnosed with cT2 or lower, but with preoperative positive voided urine cytology and/or tumor diameter ≥ 3 cm need to be considered for treatment as cT3.

Single-Cell Phenotyping of CD73 Expression Reveals the Diversity of the Tumor Immune Microenvironment and Reflects the Prognosis of Bladder Cancer.

The cutting edge of cancer immunotherapy extends to ecto-5'-nucleotidase (CD73), a cell membrane enzyme that targets the metabolism of extracellular adenosine. We herein focused on the expression of CD73 to clarify the state of CD73 positivity in cancer immunity and tumor microenvironment, thereby revealing a new survival predictor for patients with bladder cancer (BCa). We used clinical tissue microarrays of human BCa and simultaneously performed the fluorescent staining of cell type-specific markers (CD3, CD8, Foxp3, programmed cell death protein 1, and programmed death-ligand 1 [PD-L1]) and CD73 together with DAPI for nuclear staining. In total, 156 participants were included. Multiplexed cellular imaging revealed a unique interaction between CD73 expression and CD8+ cytotoxic T cells (CTLs) and Foxp3+ regulatory T (Treg) cells in human BCa, showing the high infiltration of CD8+CD73+ CTLs and Foxp3+CD73+ Treg cells in tumors to be associated with tumorigenesis and poor prognosis in BCa. Interestingly, from a biomarker perspective, the high infiltration of CD73+ Treg cells in tumors was identified as an independent risk factor for overall survival in addition to clinicopathologic features. Regarding the relationship between immune checkpoint molecules and CD73 expression, both CD73+ CTLs and CD73+ Treg cells tended to coexpress programmed cell death protein 1 as tumor invasiveness and nuclear grade increased. Additionally, they may occupy a spatial niche located distantly from PD-L1+ cells in tumors to interfere less with the cancerous effects of PD-L1+ cells. In conclusion, the present results on the status of CD73 in cancer immunity suggest that CD73 expression on specific T-cell types has a negative immunoregulatory function. These findings may provide further insights into the immunobiological landscape of BCa, which may be translationally linked to improvements in future immunotherapy practice.

Prognostic role of the innate immune signature CD163 and "eat me" signal calreticulin in clear cell renal cell carcinoma.

The effects of the innate immune status on patients with clear cell renal cell carcinoma (ccRCC) currently remain unknown. We herein provided more extensive information about the inner landscape of immunobiology of ccRCC. In total, 260 ccRCC samples from three different cohorts consisting of 213 primary tumors and 47 metastases were obtained. We focused on five representative innate immune signatures, CD68, CD163, the "eat me" signal calreticulin, the "don't eat me" signal CD47, and signal regulatory protein α, and examined the role of each signature by quantitative immunohistochemistry. We then conducted an integrated genome mutation analysis by next-generation sequencing. Among the five markers, high CD163 and low calreticulin expression levels were prognostic in ccRCC. The application of a new risk model based on CD163 and calreticulin levels, named the innate immune risk group (high risk: high-CD163/low calreticulin, intermediate risk: high-CD163/high calreticulin or low CD163/low calreticulin, low risk: low-CD163/high calreticulin), enabled the sequential stratification of patient prognosis and malignancy. Although organ-specific differences were observed, metastases appeared to have a higher innate immune risk, particularly in the lungs, with 50% of ccRCC metastases being classified into the high-risk group according to our risk score. An analysis of genomic alterations based on the innate immune risk group revealed that alterations in the TP53/Cell cycle pathway were highly prevalent in high-risk ccRCC patients according to two innate immune signatures CD163 and calreticulin. The present results provide insights into the immune-genomic biology of ccRCC tumors for innate immunity and will contribute to future therapies focused on the innate immune system in solid cancers.

Predictors of Survival in Favorable Risk Patients with Metastatic Renal Cell Carcinoma Treated with a Single-Agent First-Line Therapy.

INTRODUCTION: The aim of this retrospective study was to elucidate predictors of survival in metastatic renal cell carcinoma (mRCC) patients in an International Metastatic Renal Cell Carcinoma Database Consortium favorable risk group treated with frontline therapy without immune checkpoint inhibitors. METHODS: A total of 238 patients with mRCC were reviewed. Among them, 55 patients in favorable risk group treated with single-agent systemic therapy were retrospectively analyzed. Clinical and pathological data were retrieved and analyzed retrospectively. The prognostic effect of each marker on overall survival (OS) was investigated with univariate and multivariate Cox's proportional hazards regression models. RESULTS: After a median follow-up of 46.2 months after first-line treatment initiation, the median progression-free survival (PFS) was 29.3 months, and the median OS has not been reached. The estimated percentage of patients who were alive at 12 and 24 months were 96.1 and 94.1%, respectively. Multivariate analysis revealed that the long-term duration of first-line treatment (hazard ratio [HR]: 0.972, 95% confidence interval [CI]: 0.944-0.997, p = 0.0299) and the metastases limited to lung (HR: 3.852, 95% CI: 1.080-24.502, p = 0.0361) were independent predictors for longer OS in favorable risk mRCC patients. CONCLUSION: First-line systemic therapy for favorable risk mRCC patients with a single agent resulted in relatively longer PFS and OS. A longer duration of first-line treatment and lung only metastases are correlated with longer OS.

Profiling the Biological Characteristics and Transitions through Upper Tract Tumor Origin, Bladder Recurrence, and Muscle-Invasive Bladder Progression in Upper Tract Urothelial Carcinoma.

To evaluate biological characteristics and transitions of upper tract urothelial carcinoma (UTUC) through metachronous bladder tumors after radical nephroureterectomy (RNU), we conducted immunohistochemical (IHC) staining of tumor specimens of UTUC tumor origin, non-muscle-invasive bladder cancer (NMIBC) and MIBC progressed after intravesical recurrence (IVR), and bladder primary MIBC. Fibroblast growth factor receptor 3 (FGFR3), p53, cytokeratin 5/6 (CK5/6), and CK20 were stained to examine expression rates. After expression assessment with heatmap clustering, the overexpression of four biomarkers from UTUC origin to metachronous MIBC progression was analyzed with clinicopathological variables. We found that high CK20 and low CK5/6 expression were both observed in UTUC tumor origin and subsequent NMIBC after RNU. By investigating molecular expression in the IVR specimen, we observed that low pT stage bladder recurrence occupied the majority of CK20 high CK5/6 low expression, but would change to CK20 low CK5/6 high expression as it progressed to MIBC. UTUC metachronous MIBC has different characteristics compared with bladder primary MIBC, which comprises favorable biological features such as high FGFR3 expression, and follows favorable prognosis compared to those without FGFR3 expression. The present study demonstrated that the biological characteristics of UTUC tumor origin shifts from luminal to basal-like features with progression to MIBC, but FGFR3 expression taken over from UTUC origin may comprise a favorable entity compared to primary MIBC.

The clinicopathological characteristics of muscle-invasive bladder recurrence in upper tract urothelial carcinoma.

This study aimed to clarify the clinical characteristics and oncological outcomes of patients with upper tract urothelial carcinoma (UTUC) who developed muscle-invasive bladder cancer (MIBC) after radical nephroureterectomy (RNU). We identified 966 pTa-4N0-2M0 patients with UTUC who underwent RNU and clarified the risk factors for MIBC progression after initial intravesical recurrence (IVR). We also identified 318 patients with primary pT2-4N0-2M0 MIBC to compare the oncological outcomes with those of patients with UTUC who developed or progressed to MIBC. Furthermore, immunohistochemical examination of p53 and FGFR3 expression in tumor specimens was performed to compare UTUC of MIBC origin with primary MIBC. In total, 392 (40.6%) patients developed IVR after RNU and 46 (4.8%) developed MIBC at initial IVR or thereafter. As a result, pT1 stage on the initial IVR specimen, concomitant carcinoma in situ on the initial IVR specimen, and no intravesical adjuvant therapy after IVR were independent factors for MIBC progression. After propensity score matching adjustment, primary UTUC was a favorable indicator for cancer-specific death compared with primary MIBC. Subgroup molecular analysis revealed high FGFR3 expression in non-MIBC and MIBC specimens from primary UTUC, whereas low FGFR3 but high p53 expression was observed in specimens from primary MIBC tissue. In conclusion, our study demonstrated that patients with UTUC who develop MIBC recurrence after RNU exhibited the clinical characteristics of subsequent IVR more than those of primary UTUC. Of note, MIBC subsequent to UTUC may have favorable outcomes, probably due to the different molecular biological background compared with primary MIBC.

Landscape of prognostic signatures and immunogenomics of the AXL/GAS6 axis in renal cell carcinoma.

BACKGROUND: Cabozantinib is an oral tyrosine kinase inhibitor in renal cell carcinoma (RCC), whose targets include oncogenic AXL and unique ligand GAS6. Critical gaps in basic knowledge need to be addressed to devise an exclusive biomarker and candidate when targeting the AXL/GAS6 axis. METHODS: To clarify the effects of the AXL/GAS6 axis on RCC, we herein performed a large-scale immunogenomic analysis and single-cell counts including various metastatic organs and histological subtypes of RCC. We further applied genome-wide mutation analyses and methylation arrays. RESULTS: Varying patterns of AXL and GAS6 expression were observed throughout primary RCC tumours and metastases. Scoring individual AXL/GAS6 levels in the tumour centre and invasive margin, namely, the AXL/GAS6 score, showed a good ability to predict the prognosis of clear cell RCC. Metastasis- and histological subtype-specific differences in the AXL/GAS6 score existed since lung metastasis and the papillary subtype were weakly related to the AXL/GAS6 axis. Cell-by-cell immunohistological assessments clarified an immunosuppressive environment in tumours with high AXL/GAS6 scores. Genomic alterations in the PI3K-mTOR pathway and DNA methylation profiling revealed distinct differences with the AXL/GAS6 score in ccRCC. CONCLUSION: The AXL/GAS6 scoring system could predict the outcome of prognosis and work as a robust biomarker for the immunogenomic state in RCC.

Multiplexed single-cell pathology reveals the association of CD8 T-cell heterogeneity with prognostic outcomes in renal cell carcinoma.

Despite the high sensitivity of renal cell carcinoma (RCC) to immunotherapy, RCC has been recognized as an unusual disease in which CD8+ T-cell infiltration into the tumor beds is related to a poor prognosis. To approach the inner landscape of immunobiology of RCC, we performed multiplexed seven-color immunohistochemistry (CD8, CD39, PD-1, Foxp3, PD-L1, and pan-cytokeratin AE1/AE3 with DAPI), which revealed the automated single-cell counts and calculations of individual cell-to-cell distances. In total, 186 subjects were included, in which CD39 was used as a marker for distinguishing tumor-specific (CD39+) and bystander (CD39-) T-cells. Our clear cell RCC cohort also revealed a poor prognosis if the tumor showed increased CD8+ T-cell infiltration. Intratumoral CD8+CD39+ T-cells as well as their exhausted CD8+CD39+PD-1+ T-cells in the central tumor areas enabled the subgrouping of patients according to malignancy. Analysis using specimens post-antiangiogenic treatment revealed a dramatic increase in proliferative Treg fraction Foxp3+PD-1+ cells, suggesting a potential mechanism of hyperprogressive disease after uses of anti-PD-1 antibody. Our cell-by-cell study platform provided spatial information on tumors, where bystander CD8+CD39- T-cells were dominant in the invasive margin areas. We uncovered a potential interaction between CD8+CD39+PD-1+ T-cells and Foxp3+PD-1+ Treg cells due to cell-to-cell proximity, forming a spatial niche more specialized in immunosuppression under PD-1 blockade. A paradigm shift to the immunosuppressive environment was more obvious in metastatic lesions; rather the infiltration of Foxp3+ and Foxp3+PD-1+ Treg cells was more pronounced. With this multiplexed single-cell pathology technique, we revealed further insight into the immunobiological standing of RCC.

Clinical utility of the Vesical Imaging-Reporting and Data System for muscle-invasive bladder cancer between radiologists and urologists based on multiparametric MRI including 3D FSE T2-weighted acquisitions.

OBJECTIVES: To investigate the clinical utility of the Vesical Imaging-Reporting and Data System (VI-RADS) by comparing its diagnostic performance for muscle-invasive bladder cancer (MIBC) between radiologists and urologists based on multiparametric MRI, including three-dimensional (3D) fast spin-echo (FSE) T2-weighted acquisitions. METHODS: This study included 66 treatment-naïve patients (60 men, 6 women; mean age 74.0 years) with pathologically proven bladder cancer who underwent multiparametric MRI, including 3D FSE T2-weighted imaging, before transurethral bladder tumour resection between January 2010 and November 2018. The MRI scans were categorised according to the five-point VI-RADS score by four independent readers (two board-certified radiologists and board-certified urologists each), blinded to the histopathological findings. The VI-RADS scores were compared with the postoperative histopathological diagnosis. Interobserver agreement was assessed using weighted kappa coefficients. ROC analysis and generalised estimating equations were used to evaluate the diagnostic performance. RESULTS: Forty-nine (74.2%) and 17 (25.8%) tumours were confirmed to be non-MIBC and MIBC, respectively, based on pathological examination. The interobserver agreement was good-to-excellent between all pairs of readers (range, 0.73-0.91). The urologists' sensitivity/specificity values for DCE-MRI VI-RADS scores were significantly lower than those of radiologists. No significant differences were observed for the overall VI-RADS score. The AUC for the overall VI-RADS score was 0.94, 0.92, 0.89, and 0.87 for radiologists 1 and 2 and urologists 1 and 2, respectively. CONCLUSIONS: The VI-RADS score, based on multiparametric MRI including 3D FSE T2-weighted acquisitions, can be useful for radiologists and urologists to determine the bladder cancer muscle invasion status preoperatively. KEY POINTS: • VI-RADS (using multiparametric MRI including 3D FSE T2-weighted acquisitions) achieves good to excellent interobserver agreement and has similar diagnostic performance for detecting muscle invasion by both radiologists and urologists. • The diagnostic performance of the overall VI-RADS score is high for both radiologists and urologists, particularly due to the dominant effect of diffusion-weighted imaging on the overall VI-RADS score. • The sensitivity and specificity values of the T2WI VI-RADS scores for four readers in our study (using 3D FSE T2-weighted acquisitions) were similar (with slightly higher specificity values) to previously published results (using 2D FSE T2-weighted acquisitions).

On-treatment C-reactive protein control could predict response to subsequent anti-PD-1 treatment in metastatic renal cell carcinoma.

OBJECTIVE: The aim of this study was to evaluate the clinical significance of the on-treatment C-reactive protein (CRP) status during systemic treatment as the predictive marker for the response of subsequent nivolumab monotherapy in patients with refractory metastatic renal cell carcinoma (mRCC). PATIENTS AND METHODS: A total of 73 mRCC patients treated with nivolumab were retrospectively reviewed. We evaluated the serum CRP levels before and after molecular-targeted treatments. Patients whose CRP did not exceed baseline value were defined as the CRP-control group and the others were defined as the CRP-progression group. The clinical impact of CRP-control on the efficacy of nivolumab was assessed. RESULTS: Twenty-four patients (33%) were categorized into the CRP-control group. The CRP-control group patients (median PFS not reached) had significantly longer PFS than the CRP-progression group (median PFS 11.9 months, 95% confidence interval, CI 4.1-19.8, p = 0.038). The CRP-control group had a tendency of longer OS from nivolumab initiation than the CRP-progression group (p = 0.071). By multivariate analysis, the on-treatment CRP-control was the independent predictive factor for PFS (hazard ratio HR 0.37, 95% CI 0.14-0.99, p = 0.047). CONCLUSION: The on-treatment CRP-control could be the predictive factor for the efficacy of nivolumab in refractory mRCC patients.

Review of TFEB-amplified renal cell carcinoma with focus on clinical and pathobiological aspects.

The disease entity of TFEB-amplified renal cell carcinoma (RCC) has been recently established. In this article, we review such cases. Clinically, the age of patients ranged from 28 to 83 years with a mean age of 62.8 years. The size of the tumor ranged from 1.9 to 19.5 cm with a mean size of 8.7 cm. The tumor demonstrated a variety of architectural patterns such as solid, alveolar, papillary, pseudopapillary, nested or tubular. The International Society of Urological Pathology (ISUP) grade usually corresponds to grade 3 or 4. Cytomorphology shows eosinophilic, clear, amphophilic or even oncocytic cytoplasm. Necrosis can be frequently observed. Neoplastic cells with TFEB-amplified RCC show diffuse or patchy positivity for TFEB. Fluorescence in situ hybridization frequently show the amplification of more than 10 or 20 copies of the TFEB gene. Most TFEB-amplified RCCs behave in an aggressive fashion. Metastasis frequently occurs. In conclusion, this tumor seems to be characterized by occurrence in older patients, frequent necrosis, papillary/pseudopapillary growth pattern, high-grade nuclear grade, TFEB gene amplification, and aggressive clinical behavior. In order to clarify whether this tumor is a distinct entity from previously described renal tumors or not, a further examination in a large scale study will be required in the future.

Germline Whole-Gene Deletion of FH Diagnosed from Tumor Profiling.

Hereditary leiomyomatosis and renal cell carcinoma (HL (RCC)) entails cutaneous and uterine leiomyomatosis with aggressive type 2 papillary RCC-like histology. HLRCC is caused by pathogenic variants in the FH gene, which encodes fumarate hydratase (FH). Here, we describe an episode of young-onset RCC caused by a genomic FH deletion that was diagnosed via clinical sequencing. A 35-year-old woman was diagnosed with RCC and multiple metastases: histopathological analyses supported a diagnosis of FH-deficient RCC. Although the patient had neither skin tumors nor a family history of HLRCC, an aggressive clinical course at her age and pathological diagnosis of FH-deficient RCC suggested a germline FH variant. After counseling, the patient provided written informed consent for germline genetic testing. She was simultaneously subjected to paired tumor profiling tests targeting the exome to identify a therapeutic target. Although conventional germline sequencing did not detect FH variants, exome sequencing revealed a heterozygous germline FH deletion. As such, paired tumor profiling, not conventional sequencing, was required to identify this genetic deletion. RCC caused by a germline FH deletion has hitherto not been described in Japan, and the FH deletion detected in this patient was presumed to be of maternal European origin. Although the genotype-phenotype correlation in HLRCC-related tumors is unclear, the patient's family was advised to undergo genetic counseling to consider additional RCC screening.

[Spontaneous remission of relapsed skin lesions of ALK-positive anaplastic large cell lymphoma after autologous stem cell transplantation].

A 44-year-old woman was diagnosed with anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) with clinical stage IVA (nodal and bladder involvement). Complete response (CR) was achieved after the CHOP chemotherapy; however, 12 months after the last course of chemotherapy, ALCL relapsed in the form of skin lesions without nodal involvement. After achieving a second CR with chemotherapy, autologous stem cell transplantation was performed. Two months after transplantation, the disease again relapsed as multiple skin lesions. Electron beam irradiation was performed; however, other skin lesions appeared thereafter and spontaneously disappeared. At present, 3.4 years after the transplantation, the patient is free from disease. ALK-positive ALCL relapsing as skin lesions may behave differently from the nodal relapse. An accumulation of cases is required to elucidate ALCL characteristics relapsing as skin lesions.

CDK12 and HER2 coamplification in two urothelial carcinomas with rapid and aggressive clinical progression.

Cyclin-dependent kinase 12 (CDK12), one of the key factors associated with DNA damage response pathways, is located on chromosome 17 proximal to Erb-B2 receptor tyrosine kinase 2 (ERBB2). In this report, CDK12 and ERBB2 coamplification was detected by targeted next-generation sequencing in two urothelial carcinomas. The staining intensity of the CDK12 and human epidermal growth factor receptor-2 proteins was associated with the prognosis of each urothelial carcinoma case. Our results suggest that CDK12 coamplification with ERBB2 might be associated with tumor aggressiveness and contribution to cancer pathogenesis. Therapies targeting CDK12 should be developed for these patients.

Role of the MUC1-C oncoprotein in the acquisition of cisplatin resistance by urothelial carcinoma.

Mucin 1 C-terminal subunit (MUC1-C) has been introduced as a key regulator for acquiring drug resistance in various cancers, but the functional role of MUC1-C in urothelial carcinoma (UC) cells remains unknown. We aimed to elucidate the molecular mechanisms underlying the acquisition of cisplatin (CDDP) resistance through MUC1-C oncoprotein in UC cells. MUC1-C expression was examined immunohistochemically in tumor specimens of 159 UC patients who received CDDP-based perioperative chemotherapy. As a result, moderate to high MUC1-C expression was independently associated with poor survival in UC patients. Using human bladder cancer cell lines and CDDP-resistant (CR) cell lines, we compared the expression levels of MUC1-C, multiple drug resistance 1 (MDR1), the PI3K-AKT-mTOR pathway, and x-cystine/glutamate transporter (xCT) to elucidate the biological mechanisms contributing to the acquisition of chemoresistance. MUC1-C was strongly expressed in CR cell lines, followed with MDR1 expression via activation of the PI3K-AKT-mTOR pathway. MUC1-C also stabilized the expression of xCT, which enhanced antioxidant defenses by increasing intracellular glutathione (GSH) levels. MUC1 down-regulation showed MDR1 inhibition along with PI3K-AKT-mTOR pathway suppression. Moreover, it inhibited xCT stabilization and resulted in significant decreases in intracellular GSH levels and increased reactive oxygen species (ROS) generation. The MUC1-C inhibitor restored sensitivity to CDDP in CR cells and UC murine xenograft models. In conclusion, we found that MUC1-C plays a pivotal role in the acquisition of CDDP resistance in UC cells, and therefore the combined treatment of CDDP with a MUC1-C inhibitor may become a novel therapeutic option in CR UC patients.

Difficulty in differential diagnosis for renal cancer with microscopic papillary architecture: overlapped pathological features among papillary renal cell carcinoma (RCC), mutinous tubular and spindle cell carcinoma, and unclassified RCC. Lessons from a Japanese multicenter study.

OBJECTIVES: In our multicenter study evaluating metastatic papillary renal cell carcinoma (PRCC), 29% of tumors diagnosed as PRCC in collaborative institutes were finally diagnosed as other RCCs under central review. In those tumors, mucinous tubular and spindle cell carcinoma (MTSCC) was the leading histology, followed by unclassified RCC (ucRCC). We focused on those patients with MTSCC or ucRCC. METHODS: We reviewed the processes for the pathological diagnoses of nine tumors and reviewed their clinical features. RESULTS: All of the MTSCCs and ucRCCs were positive for AMACR, which is frequently positive in PRCC. Mucin was demonstrated in 80% of the MTSCCs, and its presence is important for their diagnoses. One MTSCC was diagnosed as a mucin-poor variant. The presence of spindle cells with low-grade nuclei was suggestive of MTSCC, but the diagnosis of high-grade MTSCC was difficult. Four tumors were diagnosed as ucRCC by histological and immunohistochemical findings. Three of the four tumors were suspicious of ucRCC in the initial review due to atypical findings as PRCC. Sunitinib and interferon-α were effective for one MTSCC patient who survived for >5 years. Two MTSCC patients who were Memorial Sloan-Kettering Cancer Center poor risk had unfavorable prognoses. One patient with mucin-poor MTSCC had an indolent clinical course. Two of four ucRCC patients showed durable stable disease with targeted agents (TAs) and survived >3 years. CONCLUSION: Some MTSCC metastases progressed very slowly and poor-risk tumors progressed rapidly. Systemic therapies including TAs showed some efficacies. Some patients who have metastatic ucRCC with microscopic papillary architecture can benefit from TAs.

Significance of tumor microenvironment in acquiring resistance to vascular endothelial growth factor-tyrosine kinase inhibitor and recent advance of systemic treatment of clear cell renal cell carcinoma.

The development of systemic therapies, including vascular endothelial growth factor-tyrosine kinase inhibitors (VEGF-TKI) and mammalian target of rapamycin (mTOR) inhibitors, represents a major breakthrough in the treatment of patients with renal cell carcinoma (RCC). However, inherent resistance is observed in some patients and acquired resistance commonly develops in many patients within several months of the initiation of systemic therapies. Since these treatments rarely cure patients, their aim is to suppress tumor progression and prolong survival. Therefore, the establishment of dependable criteria that predict responses and resistance to systemic therapies is clinically important, and the underlying molecular mechanisms also need to be elucidated for the future development of more effective therapies. We herein review recent advances in research on the molecular mechanisms underlying resistance, with a focus on morphological characteristics, tumor angiogenesis, and the tumor immune microenvironment in RCC and their relationships with VEGF-TKI treatments. Recent therapies using immune checkpoint inhibitors (ICI) and newly developed VEGF-TKI also appear to be effective for advanced RCC, with stable and durable responses to ICI being observed in some RCC patients. These new drugs and their outcomes have been briefly described.

TNFAIP2 expression induces epithelial-to-mesenchymal transition and confers platinum resistance in urothelial cancer cells.

Cisplatin (CDDP)-based chemotherapy is the gold standard treatment for many types of cancer. However, the phenotypic hallmark of tumors often changes after CDDP treatment, with the acquisition of epithelial-to-mesenchymal transition (EMT) and platinum resistance. Furthermore, the mechanisms by which cancer cells acquire EMT under the control of CDDP remain unclear. Following an investigation of urothelial carcinoma (UC) before and after the acquisition of platinum resistance, we offer the new target TNFAIP2, which led to EMT and tumor invasion in platinum-treated UC cells. TNFAIP2 expression in cancer was examined at the protein and transcriptional levels. A potential target for TNFAIP2 during EMT was assessed by microarray. Clinically, upregulated TNFAIP2 expression was identified as a significant predictor of mortality following surgery in three different cohorts of patients with UC (n = 156, n = 119, and n = 54). Knockdown of TNFAIP2 resulted in upregulation of E-cadherin expression and downregulation of TWIST1 expression, which decreased motile function in platinum-resistant UC cells. TNFAIP2 overexpression led to downregulation of E-cadherin expression and upregulation of TWIST1 expression in platinum-naïve UC cells. Clinical investigation of matched pre- and post-CDDP-treated UC sections confirmed upregulation of TNFAIP2 expression in CDDP-treated tumors but downregulation of E-cadherin expression. Global gene expression analysis following TNFAIP2 knockdown identified MTDH as a positive regulator of TNFAIP2-derived EMT acquisition in cancer cells. The present results suggest a relationship between TNFAIP2 and EMT in cancers under the control of CDDP, in which MTDH expression levels in cancer cells are vital for promoting TNFAIP2-derived EMT acquisition.