Indian Hedgehog Controls Proliferation and Differentiation in Skin Tumorigenesis and Protects Against Malignant Progression

The document from July 2013 presents findings from a study on the role of Indian Hedgehog (Ihh) in skin tumorigenesis. It was discovered that the absence of Ihh in mouse models led to an increase in benign squamous papilloma formation, a higher incidence of malignant squamous cell carcinoma, and the development of metastases in the lung and lymph nodes. In sebaceous gland tumors, Ihh deficiency resulted in inhibited tumor cell differentiation. Ihh was found to stimulate cell proliferation by activating the transcription factor GLI2 in human keratinocytes and tumors. The study suggests that Ihh signaling is critical for controlling cell proliferation, differentiation, and preventing tumor malignancy. The number of mice used in the experiments varied, with specific numbers provided for different experiments, such as 19 IhhEKO mice and 17 control mice in sebaceous tumor studies, and 20 IhhEKO mice and 19 control mice for squamous papillomas and SCCs studies.