Ganglioside GD1a is a sialic acid-containing glycosphingolipid found in brain, erythrocytes, bone marrow, testis, spleen, and liver. [1] It can be shed from the surface of tumor cells into the microenvironment where it influences tumor-host cell interactions to promote tumor cell proliferation, invasion, and metastasis. Ganglioside GD1a (20 μM) also increases endothelial cell proliferation. Furthermore, ganglioside GD1a has been shown to act as a functional coreceptor for toll-like receptor 2 (TLR2), enabling the recruitment of TLR2 to lipid rafts when bound by a bacterial toxin.[2] Ganglioside GD1a mixture contains ganglioside GD1a molecular species with C18:1 and C20:1 sphingoid backbones.