A Keratin 15 Containing Stem Cell Population From the Hair Follicle Contributes to Squamous Papilloma Development in the Mouse

The study investigated the role of keratin 15+ cells from hair follicles in the development of skin tumors using a transgenic mouse model. It was found that these cells significantly contributed to the formation of papillomas within 20 weeks of promotion. Unlike their transient role in skin wound healing, keratin 15 progeny persisted in papillomas and some malignancies for extended periods. Additionally, the study revealed heterogeneity in papillomas, with about 30% of keratin 15-derived regions expressing the Ha-ras mutation. These findings indicated that keratin 15 expressing cells from hair follicles played a crucial role in the development and persistence of cutaneous papillomas, with some expressing mutations typical of cancer initiation.