POU5F1 and keloid: Aside from the characteristic histological features of abundant ECM stroma, specifically large collagen bundles (Figure S1B), hyper-cellular and inflammatory states, the keloid tissue harbors an elevated level of Octamer-4 (Oct-4) and stage specific embryonic antigen-4 (SSEA-4) positive signals randomly dispersed in the reticular dermis as compared to matched normal skin of the same donor (Figure 1A; Figure S1C).