Immunohistochemical Studies to Examine the Diagnostic and Prognostic Implications of Epithelial-to-Mesenchymal Transition in Patients with Urothelial Carcinoma of the Bladder

Abstract

In the present study, quantitative expression of epithelial-to-mesenchymal transition (EMT)–associated markers was investigated immunohistochemically and their diagnostic and prognostic significance was evaluated in patients diagnosed with non-muscle-invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC). Immunohistochemical (IHC) staining was performed in a cohort of 65 formalin-fixed and paraffin-embedded human urinary bladder tumor tissues. Tissues’ sections were obtained from archives of the Department of Pathology at SGPGIMS, India. Epithelial marker (E-cadherin), mesenchymal markers (N-cadherin and vimentin), and EMT-activating transcription factors (ATFs) (Snail and Slug) were examined for their cellular localization (membranous/cytoplasmic/nuclear) and quantitative expressions in terms of IHC score. Expression of the aforesaid markers was statistically correlated with various clinicohistopathological variables. These variables were obtained from histopathology reports and subsequent follow-up and OPD visits of patients. Impact of these markers was assessed on recurrence-free survival (RFS) in NMIBC cases and progression-free survival (PFS) in MIBC cases. The data was analyzed using SPSS 20.0 software. Focal loss of membranous E-cadherin showed statistical relevance with hematuria and tumor grade (p < 0.001, p = 0.005: independent sample t test) in MIBC patients. Novel membranous expression of N-cadherin exhibited relevance with hematuria (p = 0.011, one sample t test) in NMIBC, while membranous expression of vimentin showed correlation with tumor grade and age (p < 0.001, p < 0.001, one sample t test) in MIBC cases. Nuclear immunopositivity of Snail showed statistical association with tumor grade in both NMIBC and MIBC cases (p < 0.001, Moses non-parametric test; p < 0.001, one sample t test) and with hematuria in MIBC cases (p = 0.007, independent sample t test). Additionally, nuclear immunopositivity of Slug showed statistical association with tumor type in NMIBC and tumor grade in MIBC cases (p < 0.001, Moses non-parametric test; p < 0.001, one sample t test). Kaplan-Meier along with logrank statistics examined association between EMT profile and RFS in NMIBC cases (p < 0.001). Significant association of EMT biomarkers with clinicohistopathological outcomes may aid urologists to correlate its dynamic functions in urothelial tumorigenesis.