496 Solar simulated light induces cutaneous squamous cell carcinoma in inbred mice: A clinically relevant model to investigate T cell responses

Over one million cases of cutaneous squamous cell carcinoma (cSCC) are diagnosed annually in the United States, and approximately 4% patients develop metastases 2% die. Yet, there is a paucity clinically relevant cSCC murine models. Outbred SKH-1 mice highly susceptible to solar simulated light (SSL)-induced cSCC. However, an outbred strain limits ability evaluate MHC-restricted, antigen-specific T responses perform studies with genetically engineered mice. To address this need, inbred FVB/N, BALB/c, C57BL/6J were exposed 42 weeks SSL (cumulative dose: 856 kJ/m2 UVB 9,884 UVA). 22 257 2,967 reliably induced tumors FVB/N BALB/c median onset 38 41 weeks, respectively, delayed compared In contrast, only 15% developed apparent tumors. Most histologically as actinic keratosis, situ, or invasive Invasive had significantly decreased percentages tumor-infiltrating dendritic cells, CD4+ IFN-γ+ CD8+ granzyme B+ regulatory cells situ Progression from early late corresponded transition immune-activating immunosuppressive microenvironment. This SSL-induced model will facilitate future investigating anti-tumor genes influencing tumor formation response therapy.