The invention relates to detection of MAP-2 (microtubule associated protein-2) as a marker to determine the metastatic potential of a tumor, including tumors derived from the neural crest such as melanomas, gliomas, Schwanomas, chromocytomas and small cell lung cancer. In one aspect, the invention comprises a method for determining the metastatic potential of a tumor sample, wherein decreased levels of MAP-2 expression in a test sample relative to controls indicates that the sample has increased metastatic potential as compared to the control. In another aspect, the invention comprises a method to prevent tumor progression in metastatic melanoma by increasing levels of MAP-2 protein in cells.