PURPOSE: Urothelial carcinoma of the urinary bladder and upper tract is prevalent. By subjecting a documented transcriptome data set of urothelial carcinoma of bladder (GSE31684) to data mining and focusing on genes linked to peptidase activity (GO:0008233), we recognized C1S as the most significantly upregulated gene related to an advanced tumor status and metastasis. We subsequently analyzed the association of both C1S mRNA and its encoded protein expression with the clinical and pathological significance. MATERIALS AND METHODS: We used real-time reverse transcription polymerase chain reaction to detect C1S transcription levels in 20 cases each of urothelial carcinoma of bladder and upper tract. An immunohistochemical stain was conducted to determine C1s protein expression levels in patients with urothelial carcinoma of upper tract (n = 340) and urinary bladder (n = 295). Furthermore, we examined the correlation of C1s expression with clinicopathological characteristics, disease-specific survival, and metastasis-free survival. RESULTS: C1S transcription levels were significantly high in patients with advanced-stage tumors of both groups (all P < .05). Immunohistochemical analysis revealed that C1s expression levels were significantly associated with adverse clinicopathological parameters in both groups of urothelial carcinoma (all P < .05). C1s overexpression predicted poor disease-specific and metastasis-free survival rates for both urothelial carcinoma groups in the univariate analysis, and it was also an independent prognostic factor in the multivariate analysis (all P < .05). CONCLUSIONS: C1s may play a pivotal role in urothelial carcinoma progress and can represent a vital prognostic marker and a promising new therapeutic target in urothelial carcinoma.
