Immunohistochemical staining of embryonic stem cells (ESCs) proteins SOX2, OCT4, Nanog and Nestin in non-cancerous nasopharyngeal tissues and nasopharyngeal carcinoma (NPC).

<p>Nuclear SOX2 expression was low in non-tumoral epithelium (A), whereas it was highly expressed in NPC tissues (B). Nuclear staining of OCT4 was limited to basal cells of non-tumoral epithelium (D; arrows indicated) and markedly expressed in tumor cells (E). Low cytoplasmic expression of Nanog was observed in non-tumoral epithelium (G) and strongly displayed in tumor tissues (H). Nestin expression was completely absent in non-cancerous epithelium (J) and tumor cells (K), whereas it was strongly stained in the cytoplasm of endothelial cells in cancer tissues (K; arrows indicated). Immunofluorescent labeling of both SOX2 (C) and OCT4 (C) showed nuclear staining (red), Nanog (I) and Nestin (L) showed cytoplasmic localization (red) of tumor cells and endothelial cells, respectively, DAPI (blue).All images, ×400.</p

Influence of SOX2, OCT4 and Nanog expression on overall survival of NPC patients.

<p>There was no significant difference in the overall survival between low and high nuclear SOX2 expression(A). Patients showed worse overall survival with high nuclear OCT4 (B), cytoplasmic Nanog (C) and coexpression of OCT4 and Nanog (D) in tumors. Patients with high expression of nuclear SOX2 (E), nuclear OCT4 (F), cytoplasmic Nanog (G) and coexpression of OCT4 and Nanog (H) in the invasive front of tumors showed worse overall survival. <i>P</i>-values were calculated by log-rank test.</p

Immunohistochemical expression levels of SOX2, OCT4, Nanog and Nestin in the invasive front of NPC (arrows indicated).

<p>Strong staining of nuclear SOX2 (A, B) was mostly found at the tumor invasive front. High staining of nuclear OCT4 (C, D) was observed in the invasive front of tumors. Cytoplasmic Nanog expression (E, F) was particularly evident at the invasive edge of tumors. <b>Of note</b>, these cells often exhibited a fibroblast-like, spindle-shaped phenotype. On the other hand, Nestin expression in blood vessels (G, H) were distributed predominantly at the invasive front of tumors. (A, C, E, G×100; B, D, F, H×400, respectively).</p