The Mutational and Microenvironmental Landscape of Cutaneous Squamous Cell Carcinoma: A Review

Simple Summary Cutaneous squamous cell carcinoma (cSCC) is a complex disease arising from an interplay of UV-induced DNA damage, genetic mutations, and alterations in the tumor microenvironment. While most cSCC cases can be treated with surgery, metastatic and locally advanced forms have a significantly worse prognosis and limited treatment options. The high mutational burden in cSCC makes it challenging to identify true driver alterations. Beyond genetics, the tumor microenvironment and its interaction with the immune system play a critical role in cSCC progression, evidenced by differences observed between immunocompromised and immunocompetent patients. In recent years, new therapeutic approaches have emerged, including immunotherapy and EGFR inhibitors, which have shown efficacy in treating advanced cSCC. Understanding the underlying mechanisms driving cSCC is crucial for developing novel and more effective therapies. This review aims to provide a comprehensive overview of the mutational landscape and microenvironmental factors in cSCC.Abstract Cutaneous squamous cell carcinoma (cSCC) manifests through the complex interactions of UV-induced DNA damage, genetic mutations, and alterations in the tumor microenvironment. A high mutational burden is present in cSCC, as well as both cSCC precursors and normal skin, making driver genes difficult to differentiate. Despite this, several key driver genes have been identified, including TP53, the NOTCH family, CDKN2A, PIK3CA, and EGFR. In addition to mutations, the tumor microenvironment and the manipulation and evasion of the immune system play a critical role in cSCC progression. Novel therapeutic approaches, such as immunotherapy and EGFR inhibitors, have been used to target these dysregulations, and have shown promise in treating advanced cSCC cases, emphasizing the need for targeted interventions considering both genetic and microenvironmental factors for improved patient outcomes.