Gangliosides are cell surface glycosphingolipids that play important functional roles in cell-cell recognition, cell adhesion, and signal transduction. Although gangliosides are mostly expressed in neural tissue, abundant ganglioside expression has been observed in some tumors. For example, fucosylated monosialotetrahexosylganglioside (FucGM1) is normally expressed in a subset of peripheral sensory neurons and dorsal root ganglia, with occasional scattered expression on cells in the spleen, thymus, small intestine, and pancreas However, a large percentage of SCLC tumors express very high levels of FucGM1.