CD34 Expression by Hair Follicle Stem Cells Is Required for Skin Tumor Development in Mice

The study investigated the role of CD34 expression in hair follicle stem cells in skin tumor development in mice. It found that CD34 was crucial for tumor formation, as CD34 knockout (CD34KO) mice did not develop papillomas under certain conditions, unlike wild-type (WT) mice. When the carcinogen dose was increased, CD34KO mice developed fewer tumors with delayed onset, indicating CD34's role in tumor promotion rather than initiation. The research highlighted CD34's importance in activating hair follicle stem cells in response to proliferative signals, impacting skin tumorigenesis, and suggested potential therapeutic targets for skin cancer.