The co-incubation of M2 macrophages with apoptotic tumor cells (M-AC group) significantly decreased the HMGB1 level owing to the efferocytosis effect of M2 macrophages, and the addition of OMVs did not ameliorate the HMGB1 liberation due to the feeble efferocytosis inhibition ability of OMVs alone. Here, HMGB1 is linked to neoplasm.