Chondroitin sulfate (CS) is the placental receptor for the VAR2CSA malaria protein, expressed at the surface of infected erythrocytes during Plasmodium falciparum infection. Infected cells adhere to syncytiotrophoblasts or get trapped within the intervillous space by binding to a determinant in a 4-O-sulfated CS chains. However, the exact structure of these glycan sequences remains unclear. VAR2CSA-reactive CS is also expressed by tumor cells, making it an attractive target for cancer diagnosis and therapeutics. The identities of the proteoglycans carrying these modifications in placental and cancer tissues remain poorly characterized. This information is clinically relevant since presentation of the glycan chains may be mediated by novel core proteins or by a limited subset of established proteoglycans. To address this question, VAR2CSA-binding proteoglycans were affinity-purified from the human placenta, tumor tissues and cancer cells and analyzed through a specialized glycoproteomics workflow. We show that VAR2CSA-reactive CS chains associate with a heterogenous group of proteoglycans, including novel core proteins. Additionally, this work demonstrates how affinity purification in combination with glycoproteomics analysis can facilitate the characterization of CSPGs with distinct CS epitopes. A similar workflow can be applied to investigate the interaction of CSPGs with other CS binding lectins as well.

Context

Radical cystectomy continues to be associated with a significant risk of morbidity and all-cause mortality (ACM). Practice pattern data demonstrating underuse of surgery for patients with muscle-invasive and high-risk non-muscle invasive bladder cancer (BC) have been linked to the advanced age and higher comorbidity status of such patients, which suggests that rates of ACM as well as cancer-specific mortality should be incorporated into patient counseling and guideline recommendations.

Objective

To review the literature on risk assessment tools for preoperative comorbidity in BC that may aid in treatment decision-making.

Evidence acquisition

A systematic search was conducted using Ovid and Medline according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines to identify studies between 1970 and 2017 reporting on comorbidity risk assessment (CRA) tools for BC. Prospective and retrospective studies were included.

Evidence synthesis

There are no published randomized control trials comparing CRA tools for BC. Patients undergoing radical cystectomy with combined high-risk comorbidity and performance scores may face up to a sevenfold greater risk of other-cause mortality compared to those with low scores. The Charlson Comorbidity Index is one of the most widely studied indices for 90-d perioperative mortality and overall and cancer-specific survival, with an area under the receiver operating characteristic curve of up to 0.810. Prospective studies of CRA tools for BC have consistently shown that patients with higher comorbidity have worse outcomes. While not specific for BC, comorbidity indices provide useful assessment of competing risks. Competing-risks assessment tools are lacking, with limited studies assessing the impact of these tools on treatment decision-making by patients and providers. We provide the impetus for incorporation of comorbidity risks into practice guidelines when discussing treatment options with patients.

Conclusions

CRA tools should be incorporated into preoperative treatment counseling and the assessment of postoperative outcomes. While retrospective evidence supports the use of CRA tools for BC, further comparative studies evaluating the effectiveness of these tools and identifying the patients most likely to benefit from a treatment according to competing-risks assessment are needed.

Patient summary

In this review we explored the clinical evidence for comorbidity risk assessment tools in bladder cancer. We found evidence to support incorporation of comorbidity risks into practice guidelines when discussing treatment options with patients.

Context

Despite established guidelines for the treatment of muscle-invasive bladder cancer, it has been reported that radical cystectomy (RC) is markedly underused, especially among patients of advanced age and those with higher comorbidity burden and lower access to care. Understanding the interactions between patient, provider, and hospital factors may inform targeted interventions to optimize RC utilization.

Objective

To systematically review the literature regarding factors associated with RC utilization.

Evidence acquisition

A systematic search was conducted using Ovid and Medline according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines to identify studies between 1970 and 2017 reporting on RC utilization. Prospective and retrospective studies were included.

Evidence synthesis

There are no published randomized control trials on RC utilization. Variations in study quality and design precluded a formal statistical meta-analysis. RC receipt significantly depended on patient, provider, and hospital factors. Patient factors associated with lower RC use included advanced age, African American and Hispanic race/ethnicity, higher comorbidity burden, unmarried marital status, higher tumor stage and grade, and lower socioeconomic status. Provider factors associated with underutilization included lower surgeon volume and a metropolitan location. Finally, hospital factors associated with lower RC use included low hospital volume, nonacademic affiliation, and hospital location in the Midwest.

Conclusions

RC is reportedly underutilized. We found that age, race, marital status, socioeconomic factors, cancer severity, comorbidity burden, surgeon volume, and facility type and location significantly determined RC receipt. Improved understanding of the varying contributions of the risk factors according to patient, provider, and hospital determinants may assist in developing targeted interventions to improve RC utilization.

Patient summary

In this review we explored the clinical evidence for factors predicting the utilization of radical cystectomy for muscle-invasive bladder cancer. Many factors related to the patient, provider, and hospital determine whether patients receive this guideline-recommended treatment. However, there remains a lack of understanding on characterization and targeted interventions according to these levels, which may improve use.

Purpose

Enfortumab vedotin (EV) is an antibody-drug conjugate (ADC) targeting NECTIN4 (encoded by the PVRL4/NECTIN4 gene) approved for treatment-refractory metastatic urothelial cancer. Factors that mediate sensitivity or resistance to EV are unknown. In this study, we sought to (i) examine heterogeneity of NECTIN4 gene expression across molecular subtypes of bladder cancer and (ii) determine whether NECTIN4 expression mediates EV sensitivity or resistance.

Experimental design

Molecular subtyping and NECTIN4 expression data from seven muscle-invasive bladder cancer clinical cohorts (n = 1,915 total specimens) were used to assess NECTIN4 expression across molecular subtypes. The outcome of the transcriptomic analysis was relative NECTIN4 expression in the consensus molecular subtypes of bladder cancer. Expression of NECTIN4 was validated in bladder cancer cell lines. NECTIN4 was stably overexpressed or knocked down in basal and luminal bladder cancer cell lines and EV drug sensitivity assays were performed, as measured by cell proliferation and clonogenic assays.

Results

NECTIN4 expression is heterogenous across molecular subtypes of bladder cancer and significantly enriched in luminal subtypes. NECTIN4 expression is positively correlated with luminal markers GATA3, FOXA1, and PPARG across all cohorts. NECTIN4 expression is both necessary and sufficient for EV sensitivity in luminal and basal subtypes of urothelial bladder cancer cells. Downregulation of NECTIN4 leads to EV resistance.

Conclusions

Sensitivity to EV is mediated by expression of NECTIN4, which is enriched in luminal subtypes of bladder cancer. These findings may have implications for biomarker development, patient selection, and the inclusion of molecular subtyping in ongoing and future EV clinical trials.See related commentary by Teo and Rosenberg, p. 4950.

BACKGROUND:Muscle-invasive bladder cancer (MIBC) is a heterogeneous disease, and gene expression profiling has identified several molecular subtypes with distinct biological and clinicopathological characteristics. While MIBC subtyping has primarily been based on messenger RNA (mRNA), long non-coding RNAs (lncRNAs) may provide additional resolution. METHODS:LncRNA expression was quantified from microarray data of a MIBC cohort treated with neoadjuvant chemotherapy (NAC) and radical cystectomy (RC) (n = 223). Unsupervised consensus clustering of highly variant lncRNAs identified a four-cluster solution, which was characterized using a panel of MIBC biomarkers, regulon activity profiles, gene signatures, and survival analysis. The four-cluster solution was confirmed in The Cancer Genome Atlas (TCGA) cohort (n = 405). A single-sample genomic classifier (GC) was trained using ridge-penalized logistic regression and validated in two independent cohorts (n = 255 and n = 94). RESULTS:NAC and TCGA cohorts both contained an lncRNA cluster (LC3) with favorable prognosis that was enriched with tumors of the luminal-papillary (LP) subtype. In both cohorts, patients with LP tumors in LC3 (LPL-C3) were younger and had organ-confined, node-negative disease. The LPL-C3 tumors had enhanced FGFR3, SHH, and wild-type p53 pathway activity. In the TCGA cohort, LPL-C3 tumors were enriched for FGFR3 mutations and depleted for TP53 and RB1 mutations. A GC trained to identify these LPL-C3 patients showed robust performance in two validation cohorts. CONCLUSIONS:Using lncRNA expression profiles, we identified a biologically distinct subgroup of luminal-papillary MIBC with a favorable prognosis. These data suggest that lncRNAs provide additional information for higher-resolution subtyping, potentially improving precision patient management.