Another interesting study involved Temoporfin-PDT in head and neck squamous cell carcinoma (HNSCC), where increased serum levels of IL-6 were detected with a peak at 24 h, and HMGB1 with a peak at one week after treatment [68], further supporting PDT as a potent inducer of acute inflammation. Here, HMGB1 is linked to head and neck squamous cell carcinoma.