Mechanism of Sex Differences in Bladder Cancer: Evident and Elusive Sex-biasing Factors


Bladder cancer incidence is drastically higher in males than females across geographical, racial, and socioeconomic strata. Despite potential differences in tumor biology, however, male and female bladder cancer patients are still clinically managed in highly similar ways. While sex hormones and sex chromosomes have been shown to promote observed sex differences, a more complex story lies beneath these evident sex-biasing factors than previously appreciated. Advances in genomic technology have spurred numerous preclinical studies characterizing elusive sex-biasing factors such as epigenetics, X chromosome inactivation escape genes, single nucleotide polymorphism, transcription regulation, metabolism, immunity, and many more. Sex-biasing effects, if properly understood, can be leveraged by future efforts in precision medicine based on a patient’s biological sex. In this review, we will highlight key findings from the last half century that demystify the intricate ways in which sex-specific biology contribute to differences in pathogenesis as well as discuss future research directions.

LncRNA HEIH/miR-4500/IGF2BP1/c-Myc Feedback Loop Accelerates Bladder Cancer Cell Growth and Stemness


BACKGROUND: Bladder cancer (BCa) is one of the most prevalent malignancies and more common in men. An aberrantly expressed long noncoding RNA (lncRNA) hepatocellular carcinoma up-regulated EZH2-associated lncRNA (HEIH) has been reported to be implicated in the progression of many cancers, but its role in BCa remains little known. Our study intended to uncover whether and how HEIH regulates BCa progression.

MATERIALS AND METHODS: Quantitative real-time polymerase chain reaction (RT-qPCR) was adopted to determine HEIH expression in BCa cell lines. Functional experiments were performed to examine the effects of HEIH on BCa cell proliferation, apoptosis, migration, invasion and stemness. Bioinformatics analysis and mechanism experiments were conducted to investigate the regulatory relationship between HEIH and related molecules in BCa.

RESULTS: HEIH expression was observed to be significantly increased in BCa cell lines. HEIH depletion significantly hindered BCa cell proliferation, migration and invasion. Besides, HEIH up-regulated MYC proto-oncogene, and bHLH transcription factor (c-Myc) expression to promote BCa cell stemness. Moreover, HEIH served as a sponge for miR-4500 to modulate insulin-like growth factor 2 mRNA binding protein 1 (IGF2BP1) expression, thereby stabilizing c-Myc mRNA level.

CONCLUSION: Our study demonstrated a positive feedback loop of HEIH/miR-4500/IGF2BP1/c-Myc in BCa progression, offering a novel insight into a possible BCa therapy.

MHC I Expression Predicts Response to Checkpoint Inhibitors in Metastatic Urothelial Carcinoma but Lacks Prognostic Value in Localized Disease


BACKGROUND: Loss of MHC I expression is a tumoral escape mechanism, part of the process of immunoediting. MHC expression patterns and their prognostic and predictive value have not been studied in urothelial carcinoma of the bladder (UC) so far.

OBJECTIVE: To correlate the expression of MHC I and MHC II with prognosis after curative treatment, response to chemotherapy and checkpoint inhibition.

PATIENTS AND METHODS: We analyzed different patient cohorts for their expression of MHC I(HLA-A/B/C) and II (HLA-DR/DP/DQ) and examined potential correlations with prognosis and response to cisplatin-based chemotherapy or PD-1/PD-L1 directed immunotherapy.

RESULTS AND LIMITATIONS: Overall, MHC expression was analyzed in 246 patients, and complete MHC I loss was seen in 29.7% of patients. In 35% of patients aberrant tumoral expression of MHC II was observed. In a homogeneous cohort of 149 patients with cystectomy with curative intent there were no significant differences in survival between the MHC expression groups. MHC I+ and MHC II+ patients had higher infiltration densities with CD8+ T effector cells.

An analysis of 77 additional patients (cohort II) with neoadjuvant chemotherapy revealed no associations of MHC status with response defined as < pT2 pN0 in the cystectomy specimen. Lastly, we analyzed 26 patients with metastatic disease treated with PD-1/PD-L1 directed immunotherapy (cohort III, best response: 11 PD, 5 SD, 10 OR) and observed responses exclusively in MHC I+ patients (10/19 patients, 52.6). All four MHC I+ /MHC II+ /PD-L1+ patients had a progression-free interval of at least 12 months.

CONCLUSIONS: Tumoral MHC I expression is frequently lost in UC. We found no association with prognosis or response to cisplatin-based chemotherapy but response to checkpoint inhibitors was limited to MHC I+ patients.

Loss of Cxcr2 in Myeloid Cells Promotes Tumour Progression and T Cell Infiltration in Invasive Bladder Cancer


BACKGROUND: CXCR2 is a chemokine receptor expressed in myeloid cells, including neutrophils and macrophages. Pharmacological inhibition of CXCR2 has been shown to sensitize tumours to immune checkpoint inhibitor immunotherapies in some cancer types.

OBJECTIVE: To investigate the effects of CXCR2 loss in regulation of tumour-infiltrating myeloid cells and their relationship to lymphocytes during bladder tumorigenesis.

METHODS: Urothelial pathogenesis and immune contexture was investigated in an OH-BBN model of invasive bladder cancer with Cxcr2 deleted in myeloid cells (LysMCre Cxcr2flox/flox). CXCR2 gene alterations and expression in human muscle invasive bladder cancer were analysed in The Cancer Genome Atlas.

RESULTS: Urothelial tumour pathogenesis was significantly increased upon Cxcr2 deletion compared to wildtype mice. This was associated with a suppression of myeloid cell infiltration in Cxcr2-deleted bladders shortly after the carcinogen induction. Interestingly, following a transient increase of macrophages at the outset of tumour formation, an increase in T cell infiltration was observed in Cxcr2-deleted tumours. The increased tumour burden in the Cxcr2-deleted bladder was largely independent of T cells and the status of immune suppression. The Cxcr2-deleted mouse model reflected the low CXCR2 mRNA range in human bladder cancer, which showed poor overall survival.

CONCLUSIONS: In contrast to previous reports of increased CXCR2 signalling associated with disease progression and poor prognosis, CXCR2 was protective against bladder cancer during tumour initiation. This is likely due to a suppression of acute inflammation. The strategy for sensitizing checkpoint immunotherapy by CXCR2 inhibition in bladder cancer may benefit from an examination of immune suppressive status.

Urethral Melanoma – Clinical, Pathological and Molecular Characteristics


BACKGROUND: Mucosal melanoma involving the urethra is a rare disease with distinct clinical and molecular characteristics and poor outcomes. Our current knowledge is limited by the small number of reports regarding this disease.

OBJECTIVE: To describe the clinical, pathological, and molecular characteristics of urethral melanoma.

METHODS: We summarized the clinicopathologic data for 31 patients treated for urethral melanoma from 1986–2017 at our institution. Genomic data from our institutional sequencing platform MSK-IMPACT (n = 5) and gene-specific PCR data on BRAF, KIT, and/or NRAS (n = 8) were compared to genomic data of cutaneous melanomas (n = 143), vulvar/vaginal melanomas (n = 24), and primary non-melanoma urethral tumors (n = 5) from our institutional database.

RESULTS: Twenty-three patients were diagnosed with localized disease, 7 had regional/nodal involvement and one had metastases. Initial treatment included surgery in 25 patients; seven had multimodal treatment. Median follow-up was 46 months (IQR 33–123). Estimated 5-year cancer-specific survival was 45%. No significant change in survival was observed based on a year of treatment.

Primary urethral melanomas showed a higher frequency of TP53 mutations compared to cutaneous (80.0% vs. 18.2%, p = 0.006) and vulvar/vaginal melanomas (80.0 vs. 25.0%, p = 0.04). BRAF mutations were absent in urethral primaries (0% vs. 46% in cutaneous melanoma, p = 0.02). Tumor mutation burden was higher in cutaneous than urethral melanomas (p = 0.04). Urethral melanomas had a higher number of somatic alterations compared to non-melanoma urethral tumors (median 11 vs. 5, p = 0.03).

CONCLUSIONS: Our findings support a unique mutational landscape of urethral melanoma compared to cutaneous melanoma. Survival remains poor and is unchanged over the time studied.

Outcomes of Patients with Bacillus Calmette-Guérin (BCG)-Unresponsive Non-Muscle Invasive Bladder Cancer as Defined by the U.S. Food and Drug Administration


BACKGROUND: Limited data are available on the outcomes of patients with non-muscle invasive bladder cancer (NMIBC) unresponsive to intravesical bacillus Calmette-Guérin (BCG), as defined by the United States Food and Drug Administration.

OBJECTIVE: To define the outcomes of patients with BCG-unresponsive NMIBC.

METHODS: This was a retrospective, single-institution observational cohort study. Records of patients managed at our institution for BCG-unresponsive NMIBC between 2005 and 2020 were reviewed and clinical outcomes evaluated.

RESULTS: The study included 149 patients. Management was with initial radical cystectomy in 60 patients (40%) and initial bladder-sparing therapy (BST) in 89 patients (60%). Overall survival was greater among patients undergoing RC than BST (HR 1.83, 95% CI 1.04–3.22, p = 0.036), potentially due to patient selection, as no significant difference was noted for metastasis-free or cancer-specific survival. Patients opting for initial BST had high rates of treatment failure, with estimated 5-year cystectomy-free survival of only 42%. Patients who received additional lines of BST after a subsequent failure were at increased risk of having ≥pT3 or pN+ disease at cystectomy (42% for ≥2 lines BST, versus 18% for 1 line BST and 15% for initial cystectomy, p = 0.038).

CONCLUSION: Among patients who underwent initial BST for BCG-unresponsive NMIBC, rates of treatment failure were very high. Patients who underwent delayed cystectomy after ≥2 lines of BST had elevated rates of extravesical disease. Our observations emphasize the importance of recent and ongoing clinical trials in this clinical space.

Systematic Review and Meta-Analysis on the Role of Perioperative Blood Transfusion in Patients Undergoing Radical Cystectomy for Urothelial Carcinoma


BACKGROUND: Radical cystectomy (RC) is the standard of care in patients with muscle-invasive bladder cancer. The impact of perioperative red blood cell (RBC) transfusion on oncological outcomes after RC is not clearly established as the existing publications show conflicting results.

OBJECTIVES: The aim of this systematic review and meta-analysis was to investigate the prognostic role of perioperative RBC transfusion on oncological outcomes after RC.

METHODS: Systematic online search on PubMed was conducted, based on PRISMA criteria for publications reporting on RBC transfusion during RC. Publications with the following criteria were included: (I) reported data on perioperative blood transfusion; (II) Reported Hazard ratio (HR) and 95% -confidence interval (CI) for the impact of transfusion on survival outcomes. Primary outcome was the impact of perioperative RBC transfusion on recurrence-free survival (RFS), cancer-specific survival (CSS) and overall survival (OS). Risk of bias assessment was performed using Newcastle-Ottawa Scale. Statistical analysis was performed using Revman 5.4 software.

RESULTS: From 27 primarily identified publications, 19 eligible articles including 22897 patients were selected. Perioperative RBC transfusion showed no impact on RFS (Z = 1.34; p = 0,18) and significant negative impact on CSS (Z = 2.67; p = 0.008) and OS (Z = 3.22; p = 0.001). Intraoperative RBC transfusion showed no impact on RFS (Z = 0.58; p = 0.56) and CSS (Z = 1.06; p = 0.29) and OS (Z = 1.47; p = 0.14).

Postoperative RBC transfusion showed non-significant trend towards improved RFS (Z = 1.89; p = 0.06) and no impact on CSS (Z = 1.56; p = 0.12) and OS (Z = 0.53 p = 0.60).

CONCLUSION: In this meta-analysis, we found perioperative blood transfusion to be a significant predictor only for worse CSS and OS but not for RFS. This effect may be determined by differences in tumor stages and patient comorbidities for which this meta-analysis cannot control due to lack of respective raw data.