Overview of Novel Biomarkers for Management of Postchemotherapy Residual Masses in Testicular Cancer.

The diagnosis of postchemotherapy residual masses in testicular cancer must be based on the integration of clinical, imaging, and serology tests. Further validation is needed for novel biomarkers.

Tumor-repopulating cells evade ferroptosis via PCK2-dependent phospholipid remodeling.

Whether stem-cell-like cancer cells avert ferroptosis to mediate therapy resistance remains unclear. In this study, using a soft fibrin gel culture system, we found that tumor-repopulating cells (TRCs) with stem-cell-like cancer cell characteristics resist chemotherapy and radiotherapy by decreasing ferroptosis sensitivity. Mechanistically, through quantitative mass spectrometry and lipidomic analysis, we determined that mitochondria metabolic kinase PCK2 phosphorylates and activates ACSL4 to drive ferroptosis-associated phospholipid remodeling. TRCs downregulate the PCK2 expression to confer themselves on a structural ferroptosis-resistant state. Notably, in addition to confirming the role of PCK2-pACSL4(T679) in multiple preclinical models, we discovered that higher PCK2 and pACSL4(T679) levels are correlated with better response to chemotherapy and radiotherapy as well as lower distant metastasis in nasopharyngeal carcinoma cohorts.

G3BP1 and SLU7 Jointly Promote Immune Evasion by Downregulating MHC-I via PI3K/Akt Activation in Bladder Cancer.

Immune checkpoint inhibitors (ICIs) show promise as second-line treatment for advanced bladder cancer (BLCA); however, their responsiveness is limited by the immune evasion mechanisms in tumor cells. This study conduct a Cox regression analysis to screen mRNA-binding proteins and reveals an association between Ras GTPase-activating protein-binding protein 1 (G3BP1) and diminished effectiveness of ICI therapy in patients with advanced BLCA. Subsequent investigation demonstrates that G3BP1 enhances immune evasion in BLCA cells by downregulating major histocompatibility complex class I (MHC-I) through phosphoinositide 3-kinase (PI3K)/Akt signaling activation. Mechanistically, G3BP1 interacts with splicing factor synergistic lethal with U5 snRNA 7 (SLU7) to form a complex with poly(A)-binding protein cytoplasmic 1 and eukaryotic translation initiation factor 4 gamma 1. This complex stabilizes the closed-loop structure of the mRNAs of class IA PI3Ks and consequently facilitates their translation and stabilization, thereby activating PI3K/Akt signaling to downregulate MHC-I. Consistently, targeting G3BP1 with epigallocatechin gallate (EGCG) impedes immune evasion and sensitizes BLCA cells to anti-programmed cell death (PD)-1 antibodies in mice. Thus, G3BP1 and SLU7 collaboratively contribute to immune evasion in BLCA, indicating that EGCG is a precision therapeutic agent to enhance the effectiveness of anti-PD-1 therapy.

Extraperitonealization of the ileal conduit decreases the risk of parastomal hernia: A single-center, randomized clinical trial.

Parastomal hernia (PSH) is a common complication in patients receiving ileal conduit urinary diversion after radical cystectomy. In this randomized controlled clinical trial, we validate our previous finding that extraperitonealization of ileal conduit decreases incidence of PSH. In total, 104 consecutive patients undergoing radical cystectomy at Sun Yat-sen University Cancer Center are randomized 1:1 to receive either modified (extraperitonealized) ileal conduit (n = 52) or conventional ileal conduit (n = 52). Primary endpoint is incidence of radiological PSH during follow-up. Incidence of radiological PSH is lower in the modified group than in the conventional group (11.5% vs. 28.8%; p = 0.028) after a median follow-up of 32 months, corresponding to a hazard ratio of 0.374 (95% confidence interval: 0.145-0.965, p = 0.034) in the modified conduit group. The results support our previous finding that extraperitonealization of the ileal conduit is effective for reducing risk of PSH in patients receiving ileal conduit diversion.

Regular gastroscopy and colonoscopy during the evaluation of urachal cancer: do we really need them?

PURPOSE: Urachal cancer is similar to gastrointestinal adenocarcinoma in histology, and gastroscopy/colonoscopy is often administered during perioperative evaluation. However, gastroscopy and colonoscopy have corresponding disadvantages. This study discusses whether gastroscopy/colonoscopy is truly necessary for patients with urachal cancer. PATIENTS AND METHODS: A total of 166 bladder adenocarcinoma cases diagnosed at Sun Yat-sen University Cancer Center were retrospectively reviewed and divided into two groups (urachal cancer and nonurachal cancer), and perioperative evaluations were retrieved. RESULTS: There were 78 patients with urachal cancer, the median age was 48 years, and 59 were male. Perioperative gastroscopy/colonoscopy revealed 5 intestinal polyps and 1 adenoma during these evaluations, and no primary gastrointestinal cancer was found. Meanwhile, preoperative imaging evaluation did not detect significant gastrointestinal lesions. For 88 patients with nonurachal cancer, including primary bladder adenocarcinoma and metastatic tumors from gastrointestinal cancer, the median age was 56 years, and 64 were male. Preoperative imaging evaluation demonstrated 36 cases of gastrointestinal lesions, and 32 were confirmed by gastroscopy/colonoscopy; the other 4 were negative. Another 4 cases of colon cancer were detected by regular colonoscopy for suspected primary bladder adenocarcinoma. In all, 35 cases of colon cancer and 1 case of gastric cancer were identified by endoscopic examination. The diagnostic consistency of imaging and gastrointestinal endoscopy was favorable (P < 0.001), and the negative predictive value and diagnostic efficiency of imaging were 96.9% and 94.6%, respectively. CONCLUSIONS: The vast majority of gastrointestinal cancer cases can be identified by assessment of the patient's clinical symptoms, meticulous physical examination, and imaging evaluation. We recommend that gastroscopy/colonoscopy only be applied to patients with urachal cancer when the above examinations are positive.

Optimal interval timing between transurethral resection of bladder tumors and Bacillus Calmette-Guerin perfusion.

OBJECTIVE: There is no consensus regarding the best interval time between transurethral resection of a bladder tumor and Bacillus Calmette-Guerin (BCG) perfusion. This study was to explore whether the interval time has an impact on the prognosis and adverse effects. METHODS: We retrospectively reviewed the clinical data of patients who received BCG intravesical perfusion at Sun Yat-sen University Cancer Center (SYSUCC) from September 2015 to October 2021. Recurrence-free survival (RFS) and progression-free survival were the primary endpoints. Cox regression was used to explore independent predictors. The association between interval time and adverse effect grade was detected by logistic regression. Propensity score matching (PSM) was performed. RESULTS: A total of 403 patients were enrolled, the median interval time was 24 days (6-163 days), and the follow-up was 28 months (7-82 months). Eighty-eight (20.9%) patients relapsed, and 40 patients (10.0%) suffered progression. The multivariate Cox regression analysis confirmed that interval time was an independent predictor of RFS (p = 0.017). Notably, when the interval time was less than or equal to 26 days, there was a trend toward better RFS, PSM resulted in 65 matched pairs in each group, and Kaplan-Meier analysis showed that there was a significant difference in RFS between groups (p = 0.009). The logistic regression analysis showed that there was no correlation between interval time and adverse effects and their grades (p > 0.05). CONCLUSIONS: We considered that the first BCG perfusion could be performed within 2-4 weeks after surgery.

Gemcitabine/nab-paclitaxel vs gemcitabine/carboplatin for advanced urothelial carcinoma.

OBJECTIVE: To compare in a phase III trial the efficacy and safety of nanoparticle albumin-bound (nab)-paclitaxel plus gemcitabine (GA) with that of carboplatin plus gemcitabine (GCb) as a first-line treatment for patients with cisplatin-ineligible metastatic urothelial cancer (mUC). PATIENTS AND METHODS: Treatment-naive, cisplatin-ineligible patients with mUC were assigned randomly to either the GA (both nab-paclitaxel 125 mg/m2 and gemcitabine 1000 mg/m2 on Days 1 and 8, every 21 days) or GCb group (carboplatin area under the free carboplatin plasma concentration versus time curve of 4.5 on Day 1, gemcitabine 1000 mg/m2 on Days 1 and 8, every 21 days). The primary endpoint was progression-free survival (PFS). Secondary endpoints included objective response rate (ORR), disease control rate (DCR), overall survival (OS), safety, and patient-reported outcomes (PROs). RESULTS: The trial was terminated early because of slow accrual after 54 patients were enrolled: 26 in in the GA group and 28 in the GCb groups. The median PFS was 6.7 vs 5.9 months for the GA and GCb groups, respectively (P = 0.248). The median OS time was 12.1 vs 10.7 months for the GA and GCb groups, respectively (P = 0.837). The ORR and DCR were 40% vs 46.4% (P = 0.637) and 72% vs 68% (P = 0.188) in the GA and GCb groups, respectively. Patients treated with GA showed significantly lower incidence of Grade 3-4 thrombocytopenia and does reduction and delay. Although peripheral sensory neuropathy was higher in the GA arm, no Grade 3 neuropathy occurred. There was no difference in the PROs between the two groups. CONCLUSION: While not powered for comparison, first-line GA showed similar efficacy and better tolerability and might be considered a rational alternative to GCb.

Effect of chemotherapy alone or combined with immunotherapy for locally advanced or metastatic genitourinary small cell carcinoma: a real-world retrospective study.

BACKGROUND: Genitourinary small cell carcinoma is rare, and has a poor prognosis. However, effective treatment options for this disease are limited. We present a study to assess the efficacy of chemotherapy alone or combined with immunotherapy for locally advanced or metastatic genitourinary small cell carcinoma (GSCC). METHODS: We performed a retrospective analysis of patients with locally advanced or metastatic GSCC from Jan 2013 to September 2022 at Sun Yat-sen University Cancer Center. The survival and safety profiles were analyzed. RESULTS: Forty-two GSCC patients were enrolled, which included 20 with chemotherapy plus immunotherapy and 22 with chemotherapy alone. The median follow-up time was 15.13 months (95% CI, 8.84-21.42). The addition of immunotherapy to chemotherapy demonstrated no significant difference in median progression-free survival (p = 0.37). However, the median overall survival (OS) was 22.97 and 14.03 months with immunotherapy plus chemotherapy and chemotherapy alone, respectively (HR = 0.69, 95%CI 0.08-0.55, p = 0.017). Two patients with immunotherapy plus chemotherapy achieved clinical complete remission. The overall response rate for patients receiving chemotherapy combined with immunotherapy was 65%, which was higher in comparison to those treated with chemotherapy alone (50%). Univariate and multivariate analyses demonstrated that chemotherapy combined with immunotherapy independently achieved favorable OS. Four patients experienced immunotherapy-related adverse events, with one developing grade 3 hypothyroidism. CONCLUSIONS: Among patients with locally advanced or metastatic GSCC, immunotherapy combined with chemotherapy might be thought of as a potentially effective treatment option for patients with GSCC.

AhR diminishes the efficacy of chemotherapy via suppressing STING dependent type-I interferon in bladder cancer.

The induction of type-I interferons (IFN-Is) is important for the efficacy of chemotherapy. By investigating the role of amino acids in regulation of IFN-I production under chemo-drug treatment in bladder cancer (BC) cells, we find an inherent AhR-dependent negative feedback to restrain STING signaling and IFN-I production. Mechanistically, in a ligand dependent manner, AhR bridges STING and CUL4B/RBX1 E3 ligase complex, facilitating STING degradation through ubiquitin-proteasome pathway. Inhibition of AhR increases STING levels and reduces tumor growth under cisplatin or STING agonist treatment. Endogenous AhR ligands are mainly consisted of tryptophan (Trp) metabolites; dietary Trp restriction, blocking the key Trp metabolism rate-limiting enzyme IDO1 or inhibition of cellular Trp importation also show similar effect as AhR inhibition. Clinically, BC patients with higher intratumoral expression of AhR or stronger intratumoral Trp metabolism (higher IDO1 or Kyn levels) that lead to higher AhR activation show worse response rate to neoadjuvant chemotherapy (NAC).

SAVE Testis-sparing score: a multicenter retrospective study of a novel predictive tool for quantifying testicular tumors.

BACKGROUND: Testis-sparing surgery (TSS) is a safe treatment for patients with benign testicular tumors. Presently, assessments for evaluating the suitability of TSS are poorly standardized, partially because testicular anatomical elements cannot be quantitatively described. MATERIALS AND METHODS: The authors developed a scoring method known as the SAVE testis-sparing score based on four critical and accessible anatomical features of a testicular tumor. The SAVE score ranges from 0 to 8 and is divided into four risk classes ( low , medium , high , and extremely high ) to evaluate the feasibility of TSS, wherein low-risk indicates high feasibility and vice versa. This study included 444 testicular tumor patients from eight centers. Among them, 216 patients (model group: 151 patients, validation group: 65 patients) were included in the modeling analysis, and the other 228 patients from children's centers were included in the proportion analysis. Using retrospective data, patient characteristics associated with surgical methods were identified. Furthermore, a multivariate logistic regression model was built quantify the associations between these characteristics and the surgery method. The receiver operator characteristic curve was used to evaluate the classification efficiency of SAVE. RESULTS: The SAVE testis-sparing score includes size (tumor size as maximal diameter), available testicular tissue volume, volume ratio of the tumor to the testis, and the exophytic / endophytic properties of the tumor. The SAVE scoring system accurately classified the suitability of TSS based on the complexity of benign testicular tumors. CONCLUSION: The SAVE score is a reproducible and robust tool for quantitatively describing the anatomical characteristics of benign testicular tumors and guide the preoperative evaluation of TSS.

Bacterial cellulose/gum Arabic composite production by in-situ modification from lavender residue hydrolysate.

In this study, bacterial cellulose/gum Arabic composite (BC/GA) was synthesized by in-situ modification from lavender residue hydrolysate for the first time. The in-situ modification with GA adding showed great beneficial effect for BC/GA synthesis. Both the product (BC or BC/GA) yield and the product (BC or BC/GA) production per sugars consumption increased greatly by the in-situ modification when compared with the fermentation without GA adding (2.90 g/L vs. 0.91 g/L, and 0.461 g/g vs. 0.138 g/g). It is hypothesized that the combination of BC and GA is the main mechanism for the beneficial effect of the in-situ modification, and the scanning electron microscope (SEM) images confirmed this hypothesis. GA adding showed little effect on the rheological properties of lavender residue hydrolysate, and this environment was suitable for the combination of BC and GA. The in-situ modification had an obvious influence on the crystallinity index and the thermal stability of BC/GA, but affected little on its functional groups and cellulose structural framework. Besides BC/GA synthesis and structure, the in-situ modification could also alter the texture properties of BC/GA. Overall, this study can offer some useful information for the biochemical conversion from green and cost-effective lavender residue hydrolysate to attractive biomaterial BC/GA.

NFYC-37 promotes tumor growth by activating the mevalonate pathway in bladder cancer.

Dysregulation of transcription is a hallmark of cancer, including bladder cancer (BLCA). CRISPR-Cas9 screening using a lentivirus library with single guide RNAs (sgRNAs) targeting human transcription factors and chromatin modifiers is used to reveal genes critical for the proliferation and survival of BLCA cells. As a result, the nuclear transcription factor Y subunit gamma (NFYC)-37, but not NFYC-50, is observed to promote cell proliferation and tumor growth in BLCA. Mechanistically, NFYC-37 interacts with CBP and SREBP2 to activate mevalonate pathway transcription, promoting cholesterol biosynthesis. However, NFYC-50 recruits more of the arginine methyltransferase CARM1 than NFYC-37 to methylate CBP, which prevents the CBP-SREBP2 interaction and subsequently inhibits the mevalonate pathway. Importantly, statins targeting the mevalonate pathway can suppress NFYC-37-induced cell proliferation and tumor growth, indicating the need for conducting a clinical trial with statins for treating patients with BLCA and high NFYC-37 levels, as most patients with BLCA have high NFYC-37 levels.

Perivesical Fat Invasive Pattern as Prognostic Factor and Predictor of Response to Adjuvant Chemotherapy in T3 Stage Bladder Cancer.

BACKGROUND: The prognostic value of the distinction between microscopic (pT3a) and macroscopic (pT3b) perivesical fat invasions remains a subject of debate. To explore whether the pattern of perivesical fat invasion can serve as a prognostic factor to better subgroup T3 stage bladder cancer. MATERIALS AND METHODS: One hundred and forty-nine patients diagnosed with T3 stage bladder cancer at Sun Yat-sen University Cancer Center (SYSUCC) were selected for the experimental cohort in this study. Ninety-seven T3 stage bladder cancer patients with pathological slices at the Cancer Genome Atlas (TCGA) were selected as validation cohort in this study. The perivesical fat invasive pattern was examined with hematoxylin and eosin-stained pathological slides by two pathologists independently. Two different perivesical fat invasive patterns, fibrous-surrounded (FS) pattern, and nonfibrous-surrounded (NFS) pattern were assessed. RESULTS: Perivesical fat invasion pattern had a significant influence on overall survival in T3 stage bladder cancer. Compared to the NFS pattern, the FS pattern was related to a better prognosis in both the SYSUCC cohort and TCGA cohort. The patients with NFS pattern tumor who underwent cisplatin-based adjuvant chemotherapy experienced an obvious improvement compared to observation after radical cystectomy in overall survival in the SYSUCC cohort. CONCLUSION: The perivesical fat invasion pattern could predict prognosis and clinically different chemotherapeutic survival outcomes in patients with T3 stage bladder cancer after radical cystectomy.

Prognostic Value of Inflammation Biomarkers in Penile Squamous Cell Carcinoma Patients Without Distant Metastasis.

BACKGROUND: To investigate the value of the presurgical inflammatory biomarkers including C-reactive protein (CRP), albumin (ALB), C-reactive protein to albumin ratio (CAR), Glasgow prognostic score (GPS), the modified GPS (mGPS), and the high-sensitivity modified GPS (Hs-mGPS) in penile squamous cell carcinoma (PSCC) without distant metastasis and develop a tool to predict the overall survival (OS) of PSCC patients. METHODS: We retrospectively enrolled 271 PSCC patients without distant metastasis from 2006 to 2021. Patients were divided into 2 cohorts by a 7:3 ratio-a training cohort (n = 191) and a validation cohort (n = 80). We performed cox regression analyses on the training cohort and constructed a nomogram to predict OS over 1, 3, and 5 years. Data from the validation cohort was used to validate the nomogram's predictive power. RESULTS: According to Kaplan-Meier analysis, elevated CRP (P < .001), hypoalbuminemia (P = .008), higher CAR (P < .001), higher GPS score (P < .001), higher mGPS score (P < .001), and higher Hs-mGPS score (P = .015) were associated with a decreased overall survival. GPS score, along with age, pathology N stage, and grade, was found to be an independent risk factor for poor prognosis in the multivariate analysis. We constructed a nomogram based on the prespecified variables predicting 1-, 3- and 5-year OS. The C-indexes of the nomogram in the training and validation cohorts were 0.871 and 0.869, respectively. The decision curve analysis showed that the nomogram had a larger net benefit. The Kaplan-Meier curves showed significant differences between the risk groups categorized according to the nomogram (P < .001). CONCLUSIONS: Inflammation biomarkers of systemic inflammation and nutritional status play an important role in individual OS predictions for PSCC patients without distant monitoring. The establishment of the nomogram provided a tool to predict the survival of 1-, 3-, and 5-year OS in PSCC patients without distant metastasis.

Can prophylactic tamsulosin reduce the risk of urinary retention after surgery? A systematic review and meta-analysis of randomized control trials.

OBJECTIVE: The meta-analysis aimed to integrate the evidence of randomized control trials to estimate the efficacy of prophylactic tamsulosin on postoperative urinary retention (POUR). METHODS: The PubMed, Embase, Web of Science, and Cochrane Library databases were searched through 1 March 2022 using predetermined keywords. Randomized control trials reporting the preventive efficacy of prophylactic tamsulosin against POUR were identified according to the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guideline. Pooled risk ratios (RRs) were calculated using a random-effects model or a fixed-effects model based on the results of heterogeneity assessment. A meta-regression analysis was performed to explore the potential sources of heterogeneity. RESULTS: There were 14 studies with 1102 patients in the Tamsulosin group and 1119 patients in the Control group. The risk of POUR was significantly lower in the Tamsulosin group (156/1102 [14.2%] vs. 238/1119 [21.3%]; RR=0.65; 95% CI: 0.50-0.86; P =0.002; Heterogeneity: I2 =51%; P =0.01). Tamsulosin administration was associated with a higher risk of adverse events (65/614 [10.6%] vs. 39/626 [6.2%]; RR=1.72; 95% CI: 1.19-2.48; P =0.004; Heterogeneity: I2 =0%; P =0.70). The meta-regression identified the mean age of patients as the only potential source of heterogeneity. Subgroup analysis showed that the younger patients (age <50 years) might benefit more from tamsulosin intake (RR=0.36; 95% CI: 0.19-0.70; P =0.003; Heterogeneity: I2 =49%; P =0.14). CONCLUSIONS: The current meta-analysis suggested that prophylactic tamsulosin contributed to the prevention of POUR, and younger patients (<50 years) might benefit more from this preventive regimen. Tamsulosin was also associated with a higher risk of adverse events.

HER2-targeting antibody-drug conjugate RC48 alone or in combination with immunotherapy for locally advanced or metastatic urothelial carcinoma: a multicenter, real-world study.

BACKGROUND: Phase II trials showed the efficacy of anti-HER2 RC48-ADC (disitamab vedotin) for HER2-positive metastatic urothelial carcinoma (UC). This study evaluated RC48 alone verses in combination with immunotherapy for locally advanced or metastatic UC using real-world data. METHODS: This retrospective, multicenter, real-world study included patients with locally advanced or metastatic UC who received RC48 in five hospitals in China between July 2021 and April 2022. The outcomes were progression-free survival (PFS), overall survival (OS), objective response rate (ORR), disease control rate (DCR), and adverse events. RESULTS: Thirty-six patients were included. The patients were 47-87 years, and 26 (72.2%) were male. Eighteen patients received RC48 alone, and 18 received RC48 combined with a programmed death-1 antibody. The median PFS was 5.4 months. The median OS was not reached. The 6-month and 1-year PFS rates were 38.8% and 15.5%, respectively. The 1-year OS rate was 79.6%. Fourteen (38.9%) patients achieved a partial response, and the ORR was 38.9%. Eleven patients had stable disease, and the DCR was 69.4%. The median PFS for patients who received RC48 combined with immunotherapy and those who received RC48 alone was 8.5 and 5.4 months, respectively. The main treatment-related adverse events included anemia, hypoesthesia, fatigue, and elevated transaminase. No treatment-related death occurred. CONCLUSION: RC48 alone or combined with immunotherapy might benefit patients with locally advanced or metastatic UC, regardless of impaired renal function.

m5C-dependent cross-regulation between nuclear reader ALYREF and writer NSUN2 promotes urothelial bladder cancer malignancy through facilitating RABL6/TK1 mRNAs splicing and stabilization.

The significance of 5-methylcytosine (m5C) methylation in human malignancies has become an increasing focus of investigation. Here, we show that m5C regulators including writers, readers and erasers, are predominantly upregulated in urothelial carcinoma of the bladder (UCB) derived from Sun Yat-sen University Cancer Center and The Cancer Genome Atlas cohort. In addition, NOP2/Sun RNA methyltransferase family member 2 (NSUN2) as a methyltransferase and Aly/REF export factor (ALYREF) as a nuclear m5C reader, are frequently coexpressed in UCB. By applying patient-derived organoids model and orthotopic xenograft mice model, we demonstrate that ALYREF enhances proliferation and invasion of UCB cells in an m5C-dependent manner. Integration of tanscriptome-wide RNA bisulphite sequencing (BisSeq), RNA-sequencing (RNA-seq) and RNA Immunoprecipitation (RIP)-seq analysis revealed that ALYREF specifically binds to hypermethylated m5C site in RAB, member RAS oncogene family like 6 (RABL6) and thymidine kinase 1 (TK1) mRNA via its K171 domain. ALYREF controls UCB malignancies through promoting hypermethylated RABL6 and TK1 mRNA for splicing and stabilization. Moreover, ALYREF recognizes hypermethylated m5C site of NSUN2, resulting in NSUN2 upregulation in UCB. Clinically, the patients with high coexpression of ALYREF/RABL6/TK1 axis had the poorest overall survival. Our study unveils an m5C dependent cross-regulation between nuclear reader ALYREF and m5C writer NSUN2 in activation of hypermethylated m5C oncogenic RNA through promoting splicing and maintaining stabilization, consequently leading to tumor progression, which provides profound insights into therapeutic strategy for UCB.

Cutoff values of PD-L1 expression in urinary cytology samples for predicting response to immune checkpoint inhibitor therapy in upper urinary tract urothelial carcinoma.

BACKGROUND: The objective of this study was to determine the cutoff value of PD-L1 expression that can predict response to immune checkpoint inhibitor (ICI) immunotherapy for upper tract urothelial carcinoma (UTUC). METHODS: The concordance of PD-L1 expression between paired surgical resection specimens (SRSs) and urine cell blocks (UCBs) (cohort 1) was studied in a retrospective set of 58 UTUC patients to determine its suitability as a predictor of ICI immunotherapy efficacy. PD-L1 expression in UCBs obtained before neoadjuvant ICI immunotherapy was verified in a prospective set of 12 UTUC patients (cohort 2). PD-L1 (SP263 clone) expression was assessed for percentage (tumor proportional score) of tumor cell (TC) showing PD-L1 staining. RESULTS: The authors found an overall agreement of 94.4% (51 of 54) between UCBs and SRSs in cohort 1 (positive percent agreement = 100%, negative percent agreement = 93.8%, r value = 0.63). PD-L1 expression in <10% and ≥10% of tumor cells (TCs) of UCBs were the best predictors of negative (<25%) and positive (≥25%) expression in TCs of SRSs, respectively (concordance = 98.1%, r value = 0.93). These findings were verified in cohort 2: at the 10% cutoff for PD-L1 expression, the best response predictive value was 83.3% (5 of 6) in PD-L1-positive patients, and the nonresponse predictive value was 50% (3 of 6) in PD-L1-negative patients. The sensitivity, specificity, and area under the receiver operating characteristic curve values for predicting ICI immunotherapy efficacy based on PD-L1-expressing TCs in UCBs were 62.5%, 75%, and 0.688, respectively. CONCLUSIONS: Immunocytochemistry of UCBs is reliable for determining PD-L1 expression, which can predict the efficacy of ICI immunotherapy at a cutoff of 10%.