ID1 and neoplasm: According to the structure–activity relationship between anti-angiogenic target proteins (Id1 and HS) and sulfated polysaccharides, WSS25 was confirmed to inhibit Id1 expression in HMEC-1 cells and block the BMP2/Smad/Id1 signaling pathway (Figure 3), thereby reducing tumor angiogenesis and inhibiting hepatic tumor cells [95].