Updated classification of urothelial cell
cancer differentiates low-grade and high-grade
cancers, which determines potential clinical outcome. Substantial interobserver variability necessitates new
biomarkers to ensure classification.
Claudins' specific expression pattern characterizes normal tissues, different
tumor types, and defined grades of
tumor differentiation. The aim of this study was to examine the expression pattern of
claudins and proliferation marker Ki-67 in low-grade and high-grade urothelial cell
cancers compared with independent control samples of non-tumorous urothelium, as well as to reveal the predictive usefulness of
claudins. The expression of claudins-1, -2, -3, -4, -5, -7, and -10 and Ki-67 was studied with quantitative immunohistochemistry and real-time RT-PCR with relative quantification in 103 samples: 86 urothelial cell
cancers (27 low grade, 59 high grade) and 17 non-tumorous urothelia. Results were analyzed regarding overall survival and recurrence-free period as well. High-grade
tumors overall showed significantly higher
claudin-4 and Ki-67 and significantly lower claudin-7 expression when compared with low-grade ones. High-grade
tumors revealed significantly shorter overall survival in Kaplan-Meier analysis.
Claudin-4, claudin-7, and Ki-67 might be used as potential markers to differentiate low-grade and high-grade urothelial cell
cancers, thereby possibly enhancing accuracy of pathological diagnosis and adding further information to clinical outcome.