Nested Variant of Urothelial Carcinoma Is a Luminal Bladder Tumor With Distinct Coexpression of the Basal Marker Cytokeratin 5/6. Academic Article uri icon

Overview

abstract

  • OBJECTIVES: The nested variant of urothelial carcinoma (NVUC) is a rare bladder tumor that may possess a luminal molecular phenotype. We sought to determine whether a small immunohistochemical (IHC) panel using common surrogates for molecular phenotypes would reliably classify a cohort of pure NVUC cases. METHODS: IHC staining with a panel composed of markers for basal subtypes (CK5/6, CK14) and luminal subtypes (FOXA1, GATA3) was performed on pure small NVUC cases (n = 23) and 5 large NVUC cases (n = 5). Scoring of IHC stains was performed semiquantitatively. Individual cases were analyzed using previously reported IHC-based surrogates for molecular subtype. RESULTS: The phenotype of NVUC was classified as luminal from 60.1% (FOXA1+/CK5/6-) to 100% (GATA3+/CK14-) of cases using composite phenotypes. No cases possessed a basal or squamous cell carcinoma-like phenotype. The majority of small NVUC cases (69.5%) showed subset CK5/6 expression distinctly localized to the basal layers of tumor cell nests. Intratumoral heterogeneity was also noted in CK5/6 (21.7% of small NVUC cases) but no other markers. CONCLUSIONS: NVUC appears to express markers of both basal and luminal bladder tumors. Definitive gene expression profiling may be valuable to further characterize this unique histologic variant.

publication date

  • March 15, 2021

Research

keywords

  • Biomarkers, Tumor
  • Carcinoma, Transitional Cell
  • Keratin-5
  • Keratin-6
  • Urinary Bladder Neoplasms

Identity

Scopus Document Identifier

  • 85102964187

Digital Object Identifier (DOI)

  • 10.1093/ajcp/aqaa160

PubMed ID

  • 33118597

Additional Document Info

volume

  • 155

issue

  • 4