a-d, Representative immunostaining images for hair follicle stem cell markers, LHX2, KRT15, and NFATC1, in the hair follicle bulge region in (a, b) 18-week human foetal skin from two facial locations (Forehead and Cheek), (c) adult facial skin, and (d) xenografted skin organoid tissue. Note that in both foetal and xenograft hair follicles, NFATC1 expression is predominantly localized to the cytoplasm in bulge cells, while NFATC1 expression in adult facial hair follicles is nuclear-localized in hair follicle bulge region, reminiscent of previous reports showing nuclear-localized NFATC1 in mouse bulge stem cells. Arrows indicate background (BG) staining noises. Dashed boxes indicate magnified bulge regions presented on a corner of each image panel (a, c, d). Dashed brackets indicate bulge region (b). Abbr: hair shaft (HS); dermal papilla (DP); sebaceous gland (SG). Representative immunostaining images are selected from 5 independent staining on 3–5 different samples per tissue type. Scale bars: 100 μm (a, c), 50 μm (b, d). Corresponds with data in Fig. 4.