COL18A1 and neoplasm: Endostatin signals through a wide range of receptors including integrins αvβ3, αvβ5, α5β1, nucleolin, VEGFR‐1‐3, as well as GPC1‐4 receptors antagonizing the binding of VEGF to the VEGF‐1 and ‐2 receptors and inhibiting the phosphorylation of ERK, p38, Akt, p125FAK, and MAP kinases as part of its anti‐angiogenic and anti‐tumor properties [233].