Therefore, the objective of this work is to compare the response to PDT with two clinically employed PSs, Temoporfin and MAL, of CSCC and HNSCC lines and to establish a relationship with the EMT process and the activation of the GSK3β/ NFκβ pathway, in order to acquire a better knowledge of the response to the therapy and selecting the most appropriate photosensitizer for each tumour. This evidence concerns the gene GSK3B and head and neck squamous cell carcinoma.