CK14 Expression Identifies a Basal/Squamous-Like Type of Papillary Non-Muscle-Invasive Upper Tract Urothelial Carcinoma

Abstract

Object: CK14 expression is an important marker of basal/squamous-like (BASQ)-type muscle-invasive bladder carcinoma, and this molecularly defined subtype has a poor prognosis and a distinct response to chemotherapy. However, CK14 expression and its clinicopathological and molecular significance in papillary non-muscle-invasive upper tract urothelial carcinoma (NMIUTUC) remain unknown. Herein, we investigated the prognostic implications of immunohistochemical (IHC) staining for CK14 and the transcriptional characteristics associated with CK14 expression in papillary NMIUTUC. Materials and Methods: IHC staining for CK14 was conducted in 204 papillary NMIUTUC specimens. Positive CK14 IHC staining was defined as a positive signal in >0% of tumor cells. RNA sequencing data were analyzed from 8 papillary high-grade NMIUTUC specimens consisting of 4 CK14-positive and 4 CK14-negative tumors. Results: CK14 positivity was associated with a high TNM stage (p < 0.001) and a high World Health Organization grade (p = 0.003). Survival analysis showed that CK14 positivity was significantly associated with poor progression-free survival (p = 0.015; hazard ratio [HR] = 2.990; 95% confidence interval [CI] = 1.180-7.580) and was marginally associated with poor cancer-specific survival (p = 0.052; HR = 3.77; 95% CI = 0.900-15.780). Gene set enrichment analysis demonstrated that the CK14-positive tumors were associated with a basal subtype of breast cancer, squamous cell carcinoma development, p40, tumor necrosis factor α-nuclear factor-κB, and p53 pathways, and embryonic stem cells; these characteristics are reminiscent of the BASQ subtype. In addition, with a p < 0.05 and |fold change| ≥2 as the cutoffs, we identified 178 differentially expressed genes when comparing CK14-positive and CK14-negative tumors. Functional analysis of these genes revealed several networks and gene ontology terms related to the positive regulation of cellular proliferation in CK14-positive tumors. Consistent with these results, we demonstrated that the mean Ki-67 proliferative index was higher in CK14-positive tumors than it was in CK14-negative tumors (2.3 vs. 0.8%, respectively, p = 0.002). Jung et al. CK14 and BASQ-Type Papillary NMIUTUC Conclusion: CK14-positive papillary NMIUTUC is an aggressive subtype with BASQ-like molecular characteristics and dynamic proliferative activity. We propose that CK14 IHC staining can be a useful biomarker of BASQ-type papillary NMIUTUC that can be applied in daily practice with the aim of precision oncology.

Proteomic-Based Machine Learning Analysis Reveals PYGB as a Novel Immunohistochemical Biomarker to Distinguish Inverted Urothelial Papilloma From Low-Grade Papillary Urothelial Carcinoma With Inverted Growth

“…Previous studies identified metabolism, cell proliferation, immune response, and intercellular communication as constitutively altered functions in urothelial carcinoma ( 35 , 36 ). Enhanced metabolism/biosynthesis functions and decreased cell–cell interaction/adhesion, consistent with what was found in the ‘PUC-like’ IUP signatures, were previously shown to promote PUC by supporting cell proliferation and structural breakdown ( 35 , 37 – 39 ). Therefore, the results suggested altered metabolism, biosynthesis, and cell–cell interaction functions were consistent with the ‘PUC-like’ (high-risk) IUP.…”

Non-Muscle-Invasive Bladder Carcinoma with Respect to Basal Versus Luminal Keratin Expression

“…Despite the high expression of cell cycle regulatory molecules and low expression of the cell cycle progression signature, the K5/6-only group was predicted to have activated functions of tumor cell adhesion, migration, and invasion and enhanced TGF-β cascades [ 20 , 28 ]. High levels of K14 in the K5/6-only group indicate its connection to the basal-like state and migratory function, in accordance with previous reports that K14 was mainly expressed in tumors with high K5/6 and low K20 expression and K14 expression identified stemness and basal/squamous-like characteristics, including activated cellular movement, in urothelial carcinoma [ 13 , 28 ]. Parallel to this, we also found a trend of tumors showing p 53-wildtype staining clustered in the K5/6-only group compared to the K20-only group, which frequently displayed p 53 overexpression.…”

“…Figure 4 summarizes the major findings of this study. IHC staining for K5/6 and K20 is an indicator of molecular traits profoundly affected in NMIBC and closely associated with NMIBC subtypes [ 6 , 8 ]; thus, we propose K5/6 and K20 as promising biomarkers in the management of patients with NMIBC [ 16 , 28 , 43 ]. In particular, the K20-only group was significantly enriched in genes related to cell cycle, proliferation, and progression, which indicates a need for close observation of patients with NMIBC with luminal-like expression.…”

Are We Ready to Implement Molecular Subtyping of Bladder Cancer in Clinical Practice? Part 1: General Issues and Marker Expression

“…The increase in CK14 immunoreactivity was also observed at an early carcinogenesis stage, initiating the appearance of malignant lesions of the urinary bladder in a rat model [ 123 ]. Thus, the use of CK14 as a marker alternate to CK5/6 in identifying basal-like tumors at the protein level could not be effective [ 28 ], since its expression would be rather useful in identifying early BCs carrying a stem cell signature and inherent aggressive features [ 35 , 124 ]. According to the Lund classification, CK14 expression was significantly higher in UroB tumors as compared to UroA tumors (30% versus 9%, p < 0.01), with positive staining restricted to basal cells [ 65 ].…”