HMGB1 and neoplasm: Specifically, it has been shown that both in vitro and in vivo exposure of irradiated tumor cells to calreticulin, followed by the release of high mobility group protein B1 (HMGB1), has an immunoadjuvant effect that leads to DC maturation via toll-like receptor 4 (TLR4) signaling, uptake of the released tumor peptides, and cross-presentation by DC [20].