Herpes simplex viruses type 1 (HSV-1) that lack the g 1 34.5 gene are unable to replicate in the central nervous system (CNS), but maintain replication competence in actively dividing tumors. To determine if antitumor therapy by M002, a g 1 34.5À HSV that Keywords: herpes simplex virus 1; IL-12; CCL2; Neuro-2a; immunohistochemistry E radication of malignancies arising in the brain has proven to be a formidable task. As an example, highgrade malignant gliomas, the most common primary brain tumor, are almost always fatal despite aggressive surgical resection, radiotherapy and chemotherapy. Moreover, the overall 5-year survival rate for glioblastoma (GBM), the most malignant glioma, is less than 5.5% and the median survival is approximately 1 year.