SPP1 and neoplasm: However, compared to control IgG, the anti-OPN antibody markedly reduced the formation of OPN+SMA+ vessels (from >60 to 10%) and proliferative CD44v6+ cells in EC-TGFβR2KD tumours at 21 dpi, and it induced similar effects in WT tumours (Supplementary Fig. 12b, c).