Our finding of frequent B7-H3 expression in DIPG was first published by Zhou et al14 and justified clinical trials.15 B7-H3 inhibits the proliferation of CD8+ and CD4+ T cells29 and promotes the recruitment and M2-like polarization of the microglia.30,31 The predominant expression pattern of B7-H3 in human DIPG samples, in PDGFRβ+ pericytes of non-tumoral origin, was recently described for adult gliomas.32 In this sense, our work contributed to identify the DIPG secretome promoting the expression of B7-H3 in hMSCs, together with pericyte markers. Here, CD4 is linked to central nervous system cancer.