Figure 4.

PRR and AT₂R were expressed by the cancer stem cells (CSCs) in head and neck metastatic malignant melanoma (HNmMM), with ACE localizing to the endothelium of microvessels. PRR ((A), red) was expressed by the SOX2+ ((A), yellow) CSCs within the tumor nests (TNs) and some cells within the peritumoral stroma (PTS). PRR ((B), red) was also expressed by cells within the TNs and the PTS, some of which expressed OCT4+ ((B), green). ACE ((C), green) was localized to the ERG+ ((C), red) endothelium of the tumor microvessels within the PTS. AT₂R ((D), red), showed membranous expression of SOX2+ ((D), yellow) CSCs within the TNs and some cells within the PTS. AT₂R ((E), red) was localized to OCT4+ ((E), green) CSCs within the PTS. All slides were counterstained with 4′,6-diamidino-2-phenylindole ((A–E), blue). Original magnification 400×; n = 2. The inserts show enlarged views of the corresponding images.