POU5F1 and renal cell carcinoma: A subpopulation of CD105+ cells from RCC was shown to express mesenchymal markers (CD44, CD90, CD29, CD73, CD146, and vimentin), embryonic stem cell markers (Oct3/4, Nanog, Musashi, and Nestin), and the embryonic renal marker Pax2, but they lacked differentiative epithelial markers (i.e., cytokeratin—CK).