Although our results showed that GBM monocyte-derived macrophages produced sPD-L1 upon LPS activation, and sVEGFR1 promoted sPD-L1 production by GBM-educated macrophages, a variety of cell types, including tumor cells, tumor-infiltrated immunocytes and circulating immunocytes are resources of both sPD-L1 and sVEGFR1 [22–25], which could not be excluded. Here, SPDL1 is linked to neoplasm.