HMGB1 and cancer: Therefore, we speculated that RAS-derived cells may have some properties of immunogenic cell death that is induced by certain agents (e.g. anthracyclines, irradiation and hypericin-based photodynamic therapy) in a tumor prophylactic vaccination model, in which dying cancer cells’ exposure or release of several molecules (e.g. calreticulin, HSP70, HMGB1 and ATP) dictate tumor immunogenicity, and these DAMPs are able to activate various kinds of immune cells such as natural killer cells (NK), macrophages and DCs [5].