SOX9 and neoplasm: In our series we did not find reactivity of CD133 nor of CD166 in the stellate stromal cells under the epithelium, but only throughout it, just like other markers that had been studied by Chang et al. Therefore, we could hypotize that SOX9 is a marker of progenitor mesenchymal stem cells and represents a more precocius marker of stemness whose higher expression influences the tumor behavior (eg relapse).