Fig. 3.

Keratin-expressing BMDCs are in the basal layer of the papilloma epithelium. a, b GFP-positive BMDCs (red) were detected in the a papilloma epithelium and b junctional area of papilloma and adjacent hyperplastic epidermis in paraffin sections of a papilloma. c, d Groups of pan-keratin-positive BMDCs (areas of yellow broken line and white arrowheads) were detected in basal parts of the papilloma epithelium in paraffin sections (keratin-negative BMDCs: white arrows). Areas in white and magenta box in figure d are magnified. e A group of K14-positive BMDCs (areas of yellow broken line) were detected in basal epithelium of frozen papilloma section (40 µm) using a multiphoton confocal microscope (note: tumor stroma was washed out in the staining processes). Area in white box is magnified. f, g BMDCs were detected in tumor-adjacent f hyperplastic epidermis, and g hair follicles. h Pan-keratin-positive BMDCs were identified in HFs (white boxes) under the tumor mass. i BMDCs were identified in deregulated HF structure under the tumor mass. *Black and white scale bars, 50 µm