As polysialylated NCAM (polySia-NCAM) is considered to be a neural stem cell marker[13], and diffusely infiltrating astrocytomas are often referred as stem cell cancers[1], we studied for the first time whether the characteristics and clinical course of astrocytomas with and without polysialylated NCAM differ from each other. The gene discussed is NCAM1; the disease is astrocytoma (excluding glioblastoma).