KLF4 and neoplasm: One population within the tumor niche had the markers SOX2+/NANOG+/KLF4+/c-MYC+/OCT4−, and two populations in the peritumoral stroma had the markers SOX2+/NANOG+/KLF4+/c-MYC+/OCT4− and SOX2+/NANOG+/KLF4+/c-MYC+/OCT4+.