Abstract
BACKGROUND: OCT4 is a key regulator of self-renewal and pluripotency in embryonic stem cells which can potentially encode three spliced variants designated OCT4A, OCT4B and OCT4B1. Based on cancer stem cell concept, it is suggested that the stemness factors misexpressed in cancer cells and potentially is involved in tumorigenesis. OBJECTIVE: Accordingly, in this study, we investigated the potential expression of OCT4 variants in breast cancer tissues. METHODS: A total of 94 tumoral and peritumoral breast specimens were evaluated with respect to the expression of OCT4 variants using quantitative RT-PCR and immunohistochemical (IHC) analysis. RESULTS: We detected the expression of OCT4 variants in breast tumor tissues with no or very low levels of expression in peritumoral samples of the same patients. While OCT4B was highly expressed in lobular type of breast cancer, OCT4A and OCTB1 variants are highly expressed in low grade (I and II) ductal tumors. Furthermore, the results of this study revealed a considerable association between the expression level of OCT4 variants and the expression of ER, PR, Her2 and P53 factors. CONCLUSIONS: All data demonstrated a distinctive expression pattern of OCT4 spliced variants in different types of breast cancer and provide further evidence for the involvement of embryonic genes in carcinogenesis.