The Prognostic Value of Cytokeratin and Extracellular Collagen Expression in Urinary Bladder Cancer

Background: Expression levels of collagens have been implicated in the progression of various cancers and interaction with cytokeratins but are not well studied in bladder cancer (BC). Therefore, we analyzed the gene and protein expression levels of collagen 1A1 (Col1a1/COL1A1), collagen 3A1 (col3a1/COL3A1), collagen 5A2 (col5a2/COL5A2), cytokeratin 14 (krt14/CK14), and cytokeratin 17 (krt17/CK17) in urothelial BC samples of different stages. Methods: In total, 102 fresh frozen and 190 formalin-fixed and paraffin-embedded (FFPE) samples were tested using immunohistochemistry and RT-qPCR. Expression levels were correlated with clinicopathological and follow-up data. Results: Col1a1, col3a1, col5a2 and krt14 mRNA levels were significantly overexpressed in high-grade and muscle-invasive BC (MIBC) compared to low-grade and non-muscle invasive BC (NMIBC) cases. Disease-specific survival (DSS) was shorter in patients with high expression levels of col1a1 (p = 0.004), col3a1 (p = 0.004), and col5a2 (p = 0.028). CK14 (p = 0.020), COL3A1 (p = 0.006), and Col5A2 (p = 0.006) protein expression levels were significantly higher and protein expression levels of CK17 (p = 0.05) were significantly lower in MIBC compared to NMIBC. Furthermore, CK14 (p = 0.002) and COL5A2 (p = 0.006) protein expression level were significantly higher in high-grade compared to low-grade BC. DSS was shorter in patients with high expression levels of COL5A2 (p = 0.033) and CK14 (p = 0.042). Conclusion: Expression changes of collagens and cytokeratins are univariable prognostic markers in BC.