KLF4 and head and neck squamous cell carcinoma: Similarly to the HNSCC sample presented in Figure 5 (with p53 mutation), also the HNSCC sample with lost p53 gene product showed intensive Slug-staining, TGF-β1 reaction confined to scattered stroma cells at the tumor—stroma interface, as well as tumor cells which displayed vimentin combined with cytokeratin and/or with KLF4 (Figure 6).