The present invention provides fusion proteins for the detection and treatment of neuroectodermal tumors. Previous work demonstrated that chlorotoxin is specific for glial-derived or meningioma-derived tumor cells. The current invention has extended the use of chlorotoxin-cytotoxin fusion proteins to treat the whole class neuroectodermal tumors such as gliomas, meningiomas, ependymonas, medulloblastomas, neuroblastomas, gangliomas, pheochromocytomas, melanomas, PPNET's, small cell carcinoma of the lung, Ewing's sarcoma, and metastatic tumors in the brain. Also, diagnostic methods are provided for screening neoplastic neuroectodermal tumors.