NCAM is an homophilic binding glycoprotein expressed on the surface of various cells (e.g. neurons, glia, skeletal muscle, and natural killer cells), which has been correlated to invasion and distant metastasis in many human cancers, including small cell lung cancer, thyroid cancer, hepatocellular carcinomas, and glioma [37-39]. Here, ART4 is linked to small cell lung carcinoma.