The Lund taxonomy for bladder cancer classification - from gene expression clustering to cancer cell molecular phenotypes, and back again

Distinct Infiltration of T Cell Populations in Bladder Cancer Molecular Subtypes

Bladder cancer is a heterogenous disease, and molecular subtyping is a promising method to capture this variability. Currently, the immune compartment in relation to subtypes is poorly characterized. Here, we analyzed the immune compartment in bladder tumors and normal bladder urothelium with a focus on T cell subpopulations using flow cytometry and RNA sequencing. The results were investigated in relation to tumor invasiveness (NMIBC/MIBC) and molecular subtypes according to the Lund Taxonomy system. Whereas the NMIBC/MIBC differed in the overall immune infiltration only, the molecular subtypes differed both in terms of immune infiltration and immune compartment compositions. The Basal/Squamous (Ba/Sq) and genomically unstable (GU) tumors displayed increased immune infiltration compared to urothelial-like (Uro) tumors. Additionally, the GU tumors had a higher proportion of regulatory T cells within the immune compartment compared to Uro tumors. Furthermore, sequencing showed higher levels of exhaustion in CD8+ T cells from GU tumors compared to both Uro tumors and the control. Although no such difference was detected at the transcriptomic level in Uro tumors compared to the controls, CD8+ T cells in Uro tumors showed higher expression of several exhaustion markers at the protein level. Taken together, our findings indicate that depending on the molecular subtype, different immunotherapeutic interventions might be warranted.

Bladder Cancer and Artificial Intelligence: Emerging Applications

Bladder cancer is a common and heterogeneous disease that poses a significant burden to the patient and health care system. Major unmet needs include effective early detection strategy, imprecision of risk stratification, and treatment-associated morbidities. The existing clinical paradigm is imprecise, which results in missed tumors, suboptimal therapy, and disease progression. Artificial intelligence holds immense potential to address many unmet needs in bladder cancer, including early detection, risk stratification, treatment planning, quality assessment, and outcome prediction. Despite recent advances, extensive work remains to affirm the efficacy of artificial intelligence as a decision-making tool for bladder cancer management.

The Genomic Landscape of Urothelial Carcinoma with High and Low ERBB2 Expression

BACKGROUND

Recent data suggests that HER2-targeted treatment is efficacious in urothelial carcinoma (UC). We investigated the genomic, transcriptomic, and immune landscapes and clinical outcomes in UC segmented by ERBB2 expression.

METHODS

NextGen DNA/RNA sequencing was performed for 4743 UC tumors. A total of 3% (124/4125) of tumors had HER2 IHC and whole transcriptome sequencing (WTS) data. ERRB2-high and -low tumors were defined by ≥75th and <25th percentiles of ERBB2 expression, respectively. PD-L1 (SP142) positive staining was defined as ≥2+ and ≥5%. HER2 (4B5) positive staining was defined as ≥3+ and >10% or 2+ and >10% with positive HER2 in situ hybridization (ISH).

RESULTS

Of the patients who were ERBB2-high, 79% (61/77) were HER2 positive via IHC. Tumors from lower tract UC had higher ERBB2 expression compared to upper tract UC (50 v 40 median TPM (mTPM), p < 0.001). ERBB2 expression was similar between primary and metastatic tumors (47 v 47 mTPM, p = 0.95). ERBB2-high tumors had a higher prevalence of pathogenic mutations in pTERT, ERBB2, and ELF3 versus ERBB2-low tumors, p < 0.001. ERBB2-high tumors had higher expressions of ADC target genes NECTIN4 (12 v 8 mTPM) and TACSTD2 (366 v 74 mTPM) versus ERBB2-low (p < 0.001), as well as better overall survival from time of tissue sampling than ERBB2-low (HR 1.71, p < 0.001).

CONCLUSION

Our study demonstrated a high concordance between HER2 expression by IHC and ERBB2 gene expression by WTS in UC. Differences in ADC target expression between ERBB2-high vs. ERBB2-low UC may provide a rationale for combination treatment strategies with HER2-ADC. The association between high ERBB2 expression and survival advantage warrants further investigation.

Upper Tract Urothelial Carcinoma: A Rare Malignancy with Distinct Immuno-Genomic Features in the Era of Precision-Based Therapies

Upper tract urothelial carcinoma (UTUC) is a rare malignancy, occurring in 5-10% of patients diagnosed with UC, and involves the renal pelvis, calyces, or ureters. UTUC can be sporadic or hereditary as a clinical manifestation of Lynch syndrome. Therapeutic management of these patients is challenging. Following risk stratification of localized disease, patients with low-grade UTUC may undergo kidney-sparing surgery or radical nephroureterectomy (RNU) and/or chemoablation with mitomycin-c instillation to reduce recurrence. In high-grade disease, RNU followed by adjuvant chemotherapy remains the standard of care. For decades, platinum-based chemotherapy has been the cornerstone of treatment for locally advanced and metastatic disease. The aim of the present review is to summarize recent advances in UTUC's therapeutic management through the lens of its genomic and immune landscape. Accumulating knowledge on the genetic and immune aspects of UTUC tumors has increased our understanding of their underlying biology, supporting a luminal papillary, T-cell depleted contexture and enrichment in fibroblast growth factor receptor (FGFR) expression. These advances have fueled successful clinical testing of several precision-based therapeutic approaches, including immune checkpoint inhibitors (ICIs), the antibody-drug conjugates (ADCs) enfortumab vedotin and sacituzumab govitecan, and agents targeting the FGFR axis such as erdafitinib and other kinase inhibitors, allowing their entry into the therapeutic armamentarium and improving the prognosis of these patients. Not all patients respond to these precision-based targeted therapies; thus, validating and expanding the toolkit of potential biomarkers of response or resistance, including molecular subtypes, FGFR pathway gene alterations, DNA repair gene defects, tumor mutational burden (TMB), circulating tumor DNA (ctDNA), nectin-4, TROP2, and programmed death ligand-1 (PD-L1), are key to maximizing the benefit to these particular subgroups of patients.