Dataset Information

A case of solitary subependymal giant cell astrocytoma: two somatic hits of TSC2 in the tumor, without evidence of somatic mosaicism.

ABSTRACT: Subependymal giant cell astrocytoma (SEGA) is a unique brain tumor arising in tuberous sclerosis complex (TSC), an autosomal dominant inherited phacomatosis. There are several case reports of solitary SEGA without any other manifestations of TSC. Usually these cases are thought to be forme fruste of TSC due to somatic mosaicism. However, no previous reports have used molecular methodology to fully investigate mutations in TSC genes or the possibility of somatic mosaicism. Here, we report a 20-year-old woman with a brain tumor. Pathological diagnosis was consistent with SEGA, but comprehensive clinical screening found no other lesions indicative of TSC. Molecular analysis of the tumor revealed loss of heterozygosity and allelic mutation (5228G>A, R1743Q) of TSC2. To detect the small fraction of mosaic mutation in somatic cells, we developed a highly sensitive new method: triple-nested polymerase chain reaction-restriction fragment length polymorphism. The identical TSC2 missense mutation was not detected in any other tissues from the same patient, including peripheral blood, buccal mucosa, urinary sediment, nail, and hair. According to these results, this patient should be considered as having SEGA that developed from two somatic hit mutations in TSC2, rather than being a TSC2 patient with a very small fraction of somatic mosaicism.

SUBMITTER: Ichikawa T

PROVIDER: S-EPMC1888498 | biostudies-literature | 2005 Oct

REPOSITORIES: biostudies-literature

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A case of solitary subependymal giant cell astrocytoma: two somatic hits of TSC2 in the tumor, without evidence of somatic mosaicism.

Ichikawa Tomotsugu T Wakisaka Akiko A Daido Shigeru S Takao Soichiro S Tamiya Takashi T Date Isao I Koizumi Shoichi S Niida Yo Y

The Journal of molecular diagnostics : JMD 20051001 4

Subependymal giant cell astrocytoma (SEGA) is a unique brain tumor arising in tuberous sclerosis complex (TSC), an autosomal dominant inherited phacomatosis. There are several case reports of solitary SEGA without any other manifestations of TSC. Usually these cases are thought to be forme fruste of TSC due to somatic mosaicism. However, no previous reports have used molecular methodology to fully investigate mutations in TSC genes or the possibility of somatic mosaicism. Here, we report a 20-ye ...[more]

PMID: 16237225

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Project description:Neurofibromatosis type-1 is a familial genetic syndrome associated with a predisposition to develop peripheral and central nervous system neoplasms. We have previously reported on a subset of gliomas developing in these patients with morphologic features resembling subependymal giant cell astrocytoma, but the molecular features of these tumors remain undefined. A total of 14 tumors were studied and all available slides were reviewed. Immunohistochemical stains and telomere-specific FISH were performed on all cases. In addition, next-generation sequencing was performed on 11 cases using a platform targeting 644 cancer-related genes. The average age at diagnosis was 28 years (range: 4-60, 9F/5M). All tumors involved the supratentorial compartment. Tumors were predominantly low grade (n = 12), with two high-grade tumors, and displayed consistent expression of glial markers. Next-generation sequencing demonstrated inactivating NF1 mutations in 10 (of 11) cases. Concurrent TSC2 and RPTOR mutations were present in two cases (1 sporadic and 1 neurofibromatosis type-1-associated). Interestingly, alternative lengthening of telomeres was present in 4 (of 14) (29%) cases. However, an ATRX mutation associated with aberrant nuclear ATRX expression was identified in only one (of four) cases with alternative lenghtening of telomeres. Gene variants in the DNA helicase RECQL4 (n = 2) and components of the Fanconi anemia complementation group (FANCD2, FANCF, FANCG) (n = 1) were identified in two alternative lenghtening of telomere-positive/ATRX-intact cases. Other variants involved genes related to NOTCH signaling, DNA maintenance/repair pathways, and epigenetic modulators. There were no mutations identified in DAXX, PTEN, PIK3C genes, TP53, H3F3A, HIST1H3B, or in canonical hotspots of IDH1, IDH2, or BRAF. A subset of subependymal giant cell astrocytoma-like astrocytomas are alternative lenghtening of telomere-positive and occur in the absence of ATRX alterations, thereby suggesting mutations in other DNA repair/maintenance genes may also facilitate alternative lenghtening of telomeres. These findings suggest that subependymal giant cell astrocytoma-like astrocytoma represents a biologically distinct group that merits further investigation.

Project description:BackgroundEverolimus, a mammalian target of rapamycin (mTOR) inhibitor, has been shown to be effective and safe in the treatment of subependymal giant cell astrocytoma (SEGA) associated with tuberous sclerosis complex (TSC). The Everolimus For Fast Expanded aCcess in TSC SEGA (EFFECTS) study was designed to provide everolimus access to patients with SEGA associated with TSC and to mainly assess the safety and also efficacy of everolimus in a real-world setting.MethodsEFFECTS was a phase 3b, open-label, noncomparative, multicenter, expanded access study. Eligible patients were ≥ 3 years of age, with a definite diagnosis of TSC, and with at least one SEGA lesion identified by MRI or CT scan. Patients received once daily everolimus (dose adjusted to attain a trough level of 5-15 ng/mL). Safety evaluation was the primary objective and included collection of adverse events (AEs) and serious AEs, with their severity and relationship to everolimus. Efficacy evaluation, which was the secondary objective, was based on the best overall response as per medical judgment.ResultsOf the 120 patients enrolled, 100 (83.3%) completed the study. Median age of patients was 11 years (range, 1-47). Median daily dose of everolimus was 5.82 mg (range, 2.0-11.8). Median duration of exposure was 56.5 weeks (range, 0.3-130). The overall incidence of AEs was 74.2%. Aphthous stomatitis (18 [15.0%]), pyrexia (18 [15.0%]), bronchitis (11 [9.2%]), and stomatitis (10 [8.3%]) were the most common AEs reported. Overall, 25 patients had grade 3 AEs; most frequent was stomatitis (4 [3.3%]). Grade 4 AEs were reported in three (2.5%) patients. A total of 62 (51.7%) patients had suspected drug-related AEs, of which 15 (12.5%) were of grade 3 or 4. In eight (6.7%) patients, AEs led to drug discontinuation. With regard to efficacy, 81 (67.5%) patients had a partial response, 35 (29.2%) had a stable disease, and one (0.8%) had progressive disease. The response was unknown in three (2.5%) patients.ConclusionThis study confirms the acceptable safety profile of everolimus in patients with SEGA associated with TSC in a real-world setting. The results further support the efficacy of everolimus in the treatment of SEGA associated with TSC. (EudraCT: 2010-022583-13).

Dataset Information

A case of solitary subependymal giant cell astrocytoma: two somatic hits of TSC2 in the tumor, without evidence of somatic mosaicism.

Publications

A case of solitary subependymal giant cell astrocytoma: two somatic hits of TSC2 in the tumor, without evidence of somatic mosaicism.

Similar Datasets

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