When apoptosis was blocked by genetic deletion of p53, 30% to 40% of N1ICD;GFAP-cre;p53(+/-) and N1ICD;GFAP-cre;p53(-/-) mice developed spontaneous medulloblastomas.
Moreover, after Abacavir exposure we detected, by immunofluorescence staining, increased protein expression of the glial marker glial fibrillary acidic protein and the neuronal marker synaptophysin in both medulloblastoma cell lines.
To clarify the effect of GFAP expression in brain tumour cells, transfer of the GFAP gene into the human medulloblastoma cell line, DAOY-1 (which does not express GFAP) was carried out using liposomes.
We found that neoplastic cells expressed beta-tubulin in 91% of the tumors (23 classic and 10 desmoplastic), synaptophysin in 75% (19 classic and 8 desmoplastic), S-Ag in 44% (11 classic and 5 desmoplastic), and GFAP in 11% of medulloblastomas (2 classic and 2 desmoplastic).