TBCE and papilloma: We have reported here significant findings in the context of the classical murine model of chemically induced skin cancer: the recruitment, keratinization, stratification, and in situ proliferation of BMDCs in papillomas and dysplastic ulcers, as well as the keratinization of plastic-adherent BMCs in vitro in the absence of direct contact with epidermal KCs or fusion, and the contributions of BMDECs and the progeny of HF bulge stem cells to papillomas.