Nestin is a type VI intermediate filament protein expressed mostly in nerve cells and implicated in the radial growth of the axon. Increased expression has been reported in melanoma, and in tumors of the CNS, including astrocytoma, ependymoma, oligodendroglioma, glioblastoma, and primitive neuroectodermal tumors, and in others carcinomas, such as prostatic adenocarcinoma, pancreatic ductal carcinoma, thyroid carcinoma, and in mesenchymal tumors.