SQUAMOUS CELL carcinoma of the skin has a good prognosis, and metastatic spread is extremely rare. This biological behavior is in striking contrast to squamous cell carcinoma of the oral cavity, the hypopharynx, or the visceral organs. It is still unknown which mechanisms render squamous cell carcinoma of the skin less aggressive than squamous cell carcinoma of other body sites.
The skin immune system, or skin-associated lymphoid tissue,1 is a potential candidate to regulate the biological behavior of skin tumors. There is experimental evidence that UV light can induce skin cancer and enhance the growth and spread of transplantable tumors.2 Furthermore, research has shown that the propagating effects of UV light on skin tumor growth are mediated by immunosuppression and can be transferred by means of suppressor T lymphocytes.3,4 Similar propagating effects have been found after administration of other immunosuppressive measures in animal experiments.5 Humans prone
Smolle J, Wolf P. Is Favorable Prognosis of Squamous Cell Carcinoma of the Skin Due to Efficient Immune Surveillance?. Arch Dermatol. 1997;133(5):645-646. doi:10.1001/archderm.1997.03890410101014