Expression profile of undifferentiated cell transcription factor 1 in normal and cancerous human epithelia

Undifferentiated cell Transcription Factor 1 (UTF1) is a chromatin-bound protein involved in stem cell differentiation. It was initially reported to be restricted to stem cells or germinal tissues. However, recent work suggests that UTF1 is also expressed in somatic cells and that its expression may increase during carcinogenesis. To further clarify the expression profile of UTF1, we evaluated UTF1 expression levels immunohistochemically in eight normal human epithelia (from breast, prostate, endometrium, bladder, colon, oesophagus, lung and kidney) and their corresponding tumours as well as in several epithelial cell lines. We showed UTF1 staining in normal and tumour epithelial tissues, but with varying intensities according to the tissue location. In vitro analyses also revealed that UTF1 is expressed in somatic epithelial cell lines even in the absence of Oct4A and Sox2, its two main known regulators. The comparison of UTF1 levels in normal and tumoral tissues revealed significant overexpression in endometrial and prostatic adenocarcinomas, whereas lower intensity of the staining was observed in renal and colic tumours, suggesting a potential tissue-specific function of UTF1. Altogether, these results highlight a potential dual role for UTF1, acting either as an oncogene or as a tumour suppressor depending on the tissue. These findings also question its role as a specific marker for stem cells.