Subependymal giant cell astrocytoma: a clinicopathological study of 23 cases with special emphasis on proliferative markers and expression of p53 and retinoblastoma gene proteins.
Mutations of the MAPK/TSC/mTOR pathway characterize periventricular glioblastoma with epithelioid SEGA-like morphology-morphological and therapeutic implications.
Ten patients (six males, four females; median age 14.23 years) with TSC-related SEGA who met inclusion criteria were included into a single-arm, prospective trial.
Enhanced expression of these growth factors and growth factor receptors in human SEGAs and tubers and in the Tsc1(GFAP)CKO mouse may account for enhanced cellular growth and proliferation in tubers and SEGAs and provides potential target molecules for therapeutic development in TSC.
We also briefly review two important advances in this area: the treatment of medulloblastomas in patients with mutations in the PTCH1 gene, and the discovery of deregulated mammalian target of rapamycin as a major oncogenic driver molecule in patients with TSC mutations and subependymal giant cell astrocytoma.
Patients with TSC2 mutations, and especially with TSC2/PKD1 mutations, are more prone to develop SEGA earlier in childhood and should be screened for SEGA from birth.
Compared with the placebo, mTOR inhibitors significantly reduced tumor volume in both angiomyolipoma (AML) (RR = 24.69, 95% CI = 3.51,173.41, P = 0.001) and subependymal giant cell astrocytoma (SEGA) (RR = 27.85, 95% CI = 1.74,444.82, P = 0.02).
These gene products form a protein complex and normally suppress mammalian target of rapamycin (mTOR) activity. mTOR inhibitors have been used to treat subependymal glioma (SEGA) that is a brain tumor characteristic of TSC.
Everolimus is an inhibitor of the mammalian target of rapamycin (mTOR) that has been approved by the US Food and Drug Administration for the treatment of subependymal giant cell astrocytoma (SEGA) in patients with tuberous sclerosis complex (TSC).
Currently, mammalian target of rapamycin inhibitors are recommended in adult patients with tuberous sclerosis complex for the treatment of asymptomatic, growing renal angiomyolipoma that are >3 cm in diameter and pediatric or adult patients with brain lesions (subependymal giant cell astrocytoma) that either are growing or are not amenable to surgical resection.
We report a 15 year-old girl with tuberous sclerosis complex who proceeded to surgical resection of her subependymal giant cell astrocytoma after 3 months of treatment with mammalian target of rapamycin inhibition.
Examples of regrowth following discontinuation of mTOR inhibitors suggest that everolimus needs to be given indefinitely to maintain suppression of subependymal giant cell astrocytoma and other tuberous sclerosis complex-associated disease manifestations.
Expression of EGF, EGFR, HGF, c-Met, and VEGF protein, as well as hypoxia inducible factor-1α, a transcription factor that regulates VEGF levels and is also modulated by mTOR cascade activity, was enhanced in SEGAs (n = 6) and tubers (n = 10) from 15 TSC patients.
We also briefly review two important advances in this area: the treatment of medulloblastomas in patients with mutations in the PTCH1 gene, and the discovery of deregulated mammalian target of rapamycin as a major oncogenic driver molecule in patients with TSC mutations and subependymal giant cell astrocytoma.