Immunohistochemical study of the expression of Oct-4 in bladder urothelial carcinoma

Background A cancer stem cell model was proposed for bladder carcinoma, as there is a subpopulation of tumor cells capable of resisting conventional therapies and surviving treatment to facilitate recurrence and metastasis. Oct-4 is a pluripotency marker of stem cells, which has been found to be associated with worse prognosis in multiple somatic tumors. Aim We aimed to explore the expression of Oct-4 protein in urothelial carcinoma and some of its variants and also determine whether Oct-4 expression and level of expression are associated with the clinicopathological parameters such as age, sex, grade, stage, morphology, and tumor progression. Patients and methods We tested 84 urothelial tumor specimens including all grades, stages, and some variants of urothelial carcinoma for the expression of Oct-4. Two sections were prepared per case for histologic evaluation and immunohistochemical staining by Oct-4 monoclonal antibody. The immunostaining was evaluated semiquantitavely through obtaining an H-score for each case. Results All cases took up the Oct-4 stain except for low-grade tumors and carcinoma in-situ cases. The highest percentage of positive cases was seen in invasive urothelial carcinoma with variant morphology other than conventional (19.1%). Presence of Oct-4 expression was significantly associated with grade (P=0.03), histopathologic type of urothelial tumor (P 0.001), category (P 0.001), and tumor progression (P=0.001). Conversely, the level of Oct-4 expression among positive cases was not found to be associated with any of the studied parameters. Conclusion Our study calls for considering Oct-4 as a novel marker of prognostic significance that could be implemented in target therapies for urothelial carcinoma.