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. The gene discussed is TBCE; the disease is skin cancer.