Ganglioside GD2 is a tumor-associated antigen that is highly expressed in various neuroectodermal tumors, including neuroblastomas, melanomas, and retinoblastomas. It plays a role in tumor development by enhancing cell proliferation, motility, migration, adhesion, and invasion. GD2 is also considered a promising target for cancer immunotherapy, with anti-GD2 antibodies not only binding to tumor cells but also inducing rapid cell death in GD2-positive tumor cells, suggesting a new role for GD2 as a receptor that actively transduces death signals in malignant cells. In normal tissues, GD2 expression is mostly restricted to neurons, skin melanocytes, and peripheral nerves, and it is either not expressed or expressed at very low levels. The high expression of GD2 in tumor cells compared to its low expression in normal cells makes it an attractive target for monoclonal antibody therapies, which have been used in clinical trials with some success.