Gangliosides and neutral glycolipids in ependymal, neuronal and primitive neuroectodermal tumors

Neutral glycolipid and ganglioside compositions were determined on 11 epend ymal tumors, 12 medulloblastomas, 6 other neuronal tumors of the brain, 4 p eripheral neuroblastomas, 1 cerebral primitive neuroectodermal tumor (PNET) , and 1 PNET of the thoracic wall. Within the group of tumors that can demo nstrate neuronal phenotypes, there was an association between the degree of neuronal differentiation usually demonstrated by these tumors and the prop ortions of both GD1a and 1b-pathway gangliosides. The amount of globoside a lso correlated with the amount of 1b pathway gangliosides. Patients with me dulloblastomas whose 1b gangliosides made up over 15% of the total ganglios ides survived longer that those with lower proportions of 1b gangliosides. The only gangliosides in the choroid plexus papilloma were GM3 and GD1a, bu t other ependymal tumors had significant amounts of GD1b and its metabolic precursors. Ependymoma and anaplastic ependymoma had similar neutral glycol ipid compositions, which were different from subependymoma, which lacked ce ramide monohexoside and ceramide dihexoside. These differences in glycolipi d compositions suggest that there may be fundamental biological differences between these types of ependymal tumors.