Tumors of the central nervous system are difficult to treat and the median survival time for patients diagnosed with such tumors is short.Gliomas are the most common brain tumors in adults.They arise from glia and are classified by the WHO into four grades: I Pilocytic astrocyomas, Ⅱ Astrocytic (low grade-diffuse), Grade Ⅲ Anaplastic astrocytoma and grade ⅡⅡ Glioblastoma multiforme.Prox1 is a homeodomain gene related to the Drosophila gene Prospero.In Drosophila, Prospero is a key player in the asymmetric division of transient amplifying cells into terminally differentiated neurons or glia.Recently, Prox1 has been reported to be epigenetically silenced in human cancer and it has been suggested that Prox1 might be a tumor suppressor.In this study we report the expression patterns of Prox1 in astrocytic gliomas and correlate the immuno-reactivity with the histological grades of the tumors.