Evaluating the expression of oct4 as a prognostic tumor marker in bladder cancer

Abstract

Objectives: The key transcriptional regulator Oct4 is one of the self-renewal and differentiation-related factors in cancer stem cells, where it maintains "stemness" state. Cancer stem cells have been identified in a variety of solid malignancies. They are a small population of tumor cells with stem cell characteristics, which are a likely cause of relapse in cancer patients. Due to high incidence, mortality, and recurrence rates of bladder cancer and the necessity of accurate prediction of malignant behavior of the tumors, we evaluated the prognostic value of Oct4 expression in formalin-fixed paraffin-embedded (FFPE) tissues of bladder cancer.

Materials and methods: In this study, Oct4 expression was evaluated in 52 (FFPE) tissues of bladder cancer. RNA extraction from samples of 30 patients from the archive of Labbafi-Nejad Medical Centre in Tehran was performed and Oct4 expression levels were examined by semi-quantitative RT-PCR. The intracellular distribution of Oct4 protein was also determined by immunohistochemistry (IHC).

Results: The results revealed a significant correlation between the expression level of Oct4 and the tumors' grade and stage. A mostly cytoplasmic distribution of Oct4 protein was also confirmed by IHC.

Conclusion: All together, our data indicate that the expression level of Oct4 gene is correlated with the clinical and histopathological prognostic indexes of tumors and thus can be considered as a potential prognostic tumor marker.

Keywords: Bladder cancer; Cancer Stem cell; Oct4; Prognosis.

Figure 1

Reverse transcription polymerase chain reaction analysis of the expression of Oct4 and B2M in FFPE samples of 4 patients; consecutive numbers show recurrent samples of the same patient. The 100 bp DNA ladder is used as molecular size marker

Figure 2

Relative expression of Oct4 in bladder tumors with different grades (A) and stages (B). Values are shown as the mean ±SD. Low stage=stages Tis, Ta, and T1. High stage=stages T2, T3, and T4

Figure 3

Immunohistochemistry results showing the tissue distribution and subcellular localization of Oct4. Brown signals show the mostly cytoplasmic localization of Oct4 protein (A); Negative control with no primary antibody treatment (B). Slides were counterstained with Hematoxylene and Eosine