High frequency of tumor cells with nuclear Egr-1 protein expression in human bladder cancer is associated with disease progression

• Published in: BMC cancer 2009-10, Vol.9 (1), p.385-385, Article 385
• Main Authors: Egerod, Frederikke Lihme, Bartels, Annette, Fristrup, Niels, Borre, Michael, Ørntoft, Torben F, Oleksiewicz, Martin B, Brünner, Nils, Dyrskjøt, Lars
• Format: Article
• Language: English
• Subjects: Bladder cancer; Development and progression; Disease Progression; Early Growth Response Protein 1 - genetics; Early Growth Response Protein 1 - metabolism; Female; Follow-Up Studies; Gene expression; Gene Expression Regulation, Neoplastic; Genetic aspects; Humans; Male; Neoplasm Staging; Physiological aspects; Transcription factors; Urinary Bladder Neoplasms - genetics; Urinary Bladder Neoplasms - metabolism; Urinary Bladder Neoplasms - pathology
• ISSN: 1471-2407; 1471-2407
• DOI: 10.1186/1471-2407-9-385

Egr-1 (early growth response-1 transcription factor) has been proposed to be involved in invasion and metastasis processes of human bladder cancer, but Egr-1 protein expression levels in human bladder cancer have not been investigated. In the present study we investigated the expression levels of Egr-1 protein in early stages of human bladder cancer and correlated it to later progression. Expression of Egr-1 protein in human bladder cancer was examined by immunohistochemistry, on a tissue microarray constructed from tumors from 289 patients with non-muscle invasive urothelial bladder cancer. The frequency of tumor cells with nuclear Egr-1 immunolabelling correlated to bladder cancer stage, grade and to later progression to muscle-invasive bladder cancer (T2-4). Stage T1 tumors exhibited significantly higher frequencies of tumor cells with nuclear Egr-1 immunolabelling than Ta tumors (P = 0.001). Furthermore, Kaplan-Meier survival analysis showed that a high frequency of tumor cells with nuclear Egr-1 immunolabelling was significantly associated with a higher risk of progression to stage T2-4 (log-rank test, P = 0.035). Tumor cells with nuclear Egr-1 immunolabelling were found to localize at the tumor front in some of the tumor biopsies. The results from this study support a potential involvement of Egr-1 in the progression from non-muscle invasive bladder cancers to muscle invasive bladder cancer.