HMGB1 and neoplasm: By chromatin immunoprecipitation and RT‐qPCR analysis, we found a significant increase of gDNA in the HMGB1 immunoprecipitates from medium of the Arf1‐ablated tumor cells in comparison with that of the control cells (Figure 2d), indicating that the HMGB1‐gDNA complex was released into extracellular space from the Arf1‐ablated tumor cells.