Immunohistochemistry of cytokeratin (CK) 5/6, CD44 and CK20 as prognostic biomarkers of non‐muscle‐invasive papillary upper tract urothelial carcinoma

Abstract

Aims Immunohistochemical (IHC) staining for cytokeratin (CK) 5/6, CD44 and CK20 has been significantly associated with the prognosis of urinary bladder urothelial carcinoma, and probably reflects its molecular characteristics. We aimed to investigate the IHC‐based subgroups and their prognostic effects on non‐muscle‐invasive papillary upper tract urothelial carcinoma (UTUC). Methods and results IHC staining for CK5/6, CK20 and CD44 was analysed in 211 patients with non‐muscle‐invasive papillary UTUC. Staining was classified as showing a negative, positive or normal pattern. We found that CK5/6‐negative, CD44‐negative and CK20‐positive tumours were distinctly high‐risk subgroups that were associated with high grade (CK5/6‐negative, P < 0.001; CD44‐negative, P < 0.001; CK20‐positive, P = 0.017) and frequent intravesical recurrence (CK5/6‐negative, P = 0.002). Using survival analysis with Kaplan–Meier and log‐rank tests, we found that these IHC subgroups were correlated with poor progression‐free (CK5/6‐negative, P = 0.001; CD44‐negative, P = 0.009; CK20‐positive, P = 0.031) and cancer‐specific (CK5/6‐negative, P = 0.009) survival. Furthermore, CK5/6 negativity was an independent prognostic factor for shorter progression‐free (P = 0.009) and cancer‐specific (P = 0.045) survival. CK5/6 improved Harrell's C‐indices for progression‐free (0.68–0.77, P = 0.029) and cancer‐specific (0.59–0.77, P < 0.001) survival. When markers were combined, luminal‐like subtypes showed poor prognoses. Conclusions We demonstrated that IHC staining for CK5/6, CD44 and CK20 was significantly associated with the clinicopathological characteristics and prognoses of patients with non‐muscle‐invasive papillary UTUC. The IHC subgroups may be correlated with the molecular characteristics of non‐muscle‐invasive papillary UTUC.

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

“…Different studies further support the association between luminal-like type and either advanced pathological states or short survival durations in NMIBC using CK5/6 (KRT5/KRT6) and CK20 (KRT20) as surrogate protein or mRNA markers (14)(15)(16). In line with these results when studying the urinary bladder, we previously reported that papillary non-muscle-invasive upper tract urothelial carcinoma (NMIUTUC) with luminal-like, CK5/6-negative/CK20-positive, or CD44-negative/CK20positive, immunophenotypes had distinctly poor prognoses that were probably associated with altered cell adhesion and late cell cycle/proliferation functions (17,18).…”

“…Of the subclasses, a common subtype, named the BASQ subtype, harbors a high level of basal-type genes, squamous-like features, and an aggressive phenotype (10). Although the BASQ subtype is a good foundation for MIBC evaluation, the applicability of BASQ markers (CK14, CK5/6, GATA3, FOXA1) to NMIUTUC or NMIBC has been questioned by us and others (13,14,(16)(17)(18). For instance, CK5/6-negative/CK20-positive luminal-like papillary NMIUTUC had worse survival and was enriched with motility-and proliferation-associated genes (17,18).…”

“…Although the BASQ subtype is a good foundation for MIBC evaluation, the applicability of BASQ markers (CK14, CK5/6, GATA3, FOXA1) to NMIUTUC or NMIBC has been questioned by us and others (13,14,(16)(17)(18). For instance, CK5/6-negative/CK20-positive luminal-like papillary NMIUTUC had worse survival and was enriched with motility-and proliferation-associated genes (17,18). In the same way, "class 2" NMIBC defined by Hedegaard and coworkers (13) was characterized by luminal-like genetic attributes, including low KRT5, KRT6, and CD44 expression and high GATA3, FOXA1, and KRT20 expression, but it had far worse survival than the other types of NMIBC.…”

“…The mean Ki-67 proliferative index (%) was quantitatively measured using QuPath (version 0.1.2) (29) on TMA slides that were virtually scanned (Aperio AT2, Leica Biosystem, Wetzlar, Germany). For 189 patients, IHC profiles for CK5/6 and CK20 were retrieved from our previous study (17). Briefly, positive CK5/6 and CK20 IHC staining was defined as >20 and >1%, respectively.…”

Emerging Roles of Cancer Stem Cells in Bladder Cancer Progression, Tumorigenesis, and Resistance to Chemotherapy: A Potential Therapeutic Target for Bladder Cancer

“…In addition, inhibition of the hyaluronic synthases1, CD44v3, CD44v6, and CD44s resulted in the abolishment of BC growth, invasion, and angiogenesis [37]. Collectively, CD44 may serve as a good prognostic marker of BC [30,38].…”