The Carcinogenesis of the Human Scalp: An Immunometabolic-Centered View.

The human scalp is a common site of skin cancer in humans, with nonmelanoma skin cancer being exceedingly common. In this review, two dermatologists with extensive experience in cutaneous oncology will discuss unique features of the epidemiology of cancer of the scalp. Clinical observations on these common skin cancers lead to insight into the pathogenesis and potential prevention and treatment of cutaneous scalp neoplasia. Our hypothesis is that the presence of hair protects against the development of skin cancer but not by serving as a physical shield but rather by providing continuous IL-17-biased immunosurveillance. The loss of hair allows for a release from immunosurveillance, resulting in the expansion of neoplastic cells towards skin cancer. Both hair follicles and metabolic changes in stroma allow for permissiveness for tumor promotion.