HMGB1 and head and neck squamous cell carcinoma: Although, the mechanism allowing the release of HMGB1 is unknown [27], we observed a correlation between the presence of HMGB1 in the extracellular medium and the percentage of CAL27 and SQ20B cells in late apoptosis 48 h after treatment, suggesting a potential link between the intrinsic sensitivity of HNSCC cells to the EXTREME protocol and HMGB1 emission.