Protocol for inducing cutaneous squamous cell carcinoma with chronic UV and treating with 5-aminolevulinic acid photodynamic therapy in SKH-1 mice

Here, we present a protocol for establishing cutaneous squamous cell carcinoma (cSCC) in SKH-1 hairless mice using a chronic ultraviolet irradiation regimen, followed by treatment with topical 5-aminolevulinic acid photodynamic therapy (ALA-PDT). We describe steps for a 28-week UV induction schedule, standardized preparation and application of ALA cream, and precise parameters for light irradiation. The model recapitulates key stages of human photocarcinogenesis, providing a physiologically relevant system for investigating cSCC pathogenesis and assessing PDT efficacy in vivo. For complete details on the use and execution of this protocol, please refer to Chen et al.