TERT promoter mutations are highly recurrent in SHH subgroup medulloblastoma (original) (raw)
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Study of hTERT and Histone 3 Mutations in Medulloblastoma
Pathobiology, 2016
Hotspot activating mutations of the telomerase reverse transcriptase (hTERT) promoter region were recently described in several tumor types. These mutations lead to enhanced expression of telomerase, being responsible for telomere maintenance and allowing continuous cell division. Additionally, there are alternative telomere maintenance mechanisms, associated with histone H3 mutations, responsible for disrupting the histone code and affecting the regulation of transcription. Here, we investigated the clinical relevance of these mechanistically related molecules in medulloblastoma. Sixty-nine medulloblastomas, formalin fixed and paraffin embedded, from a cohort of patients aged 1.5-70 years, were used to investigate the hotspot mutations of the hTERT promoter region, i.e. H3F3A and HIST1H3B, using Sanger sequencing. We successfully sequenced hTERT in all 69 medulloblastoma samples and identified a total of 19 mutated cases (27.5%). c.-124:G>A and c.-146:G>A mutations were detec...
Comparison of clinical and molecular wnt and shh subgroups in medulloblastoma tumor cases
Turkish Neurosurgery, 2020
AIM: To determine the Wnt and SHH subtypes at the molecular level, and to compare them clinically by examining the changes in CTNNB1, AXIN, PTCH1, SMO, SUFU, and GLI1 mRNA expression in the medulloblastoma of a Turkish population determined according to patient selection criteria. In this context, the clinical distinction between Wnt and SHH groups are realized by considering the age, gender, survival time, location of the lesion, and radiological features of the patients. MATERIAL and METHODS: Molecular separation was performed by RT-PCR analysis of CTNNB1, AXIN, PTCH1, SMO, SUFU, and GLI1 mRNA expression changes. RESULTS: About 17.8% and 22.2% of the cases were included in the Wnt and the SHH group, respectively. When comparing group differences based on clinical and molecular data, 72.7% and 66.6% of matches were observed in the Wnt and the SHH group, respectively. CONCLUSION: It has been revealed that molecular analysis and grouping of patients with medulloblastoma can provide support for clinically determined subgroups.
Medulloblastoma: clinicopathological correlates of SHH, WNT, and non-SHH/WNT molecular subgroups
Acta Neuropathologica, 2011
Medulloblastoma is heterogeneous, being characterized by molecular subgroups that demonstrate distinct gene expression profiles. Activation of the WNT or SHH signaling pathway characterizes two of these molecular subgroups, the former associated with low-risk disease and the latter potentially targeted by novel SHH pathway inhibitors. This manuscript reports the validation of a novel diagnostic immunohistochemical method to distinguish SHH, WNT, and non-SHH/WNT tumors and details their associations with clinical, pathological and cytogenetic variables. A cohort (n = 235) of medulloblastomas from patients aged 0.4-52 years was studied for expression of four immunohistochemical markers: GAB1, b-catenin, filamin A, and YAP1. Immunoreactivity (IR) for GAB1 characterizes only SHH tumors and nuclear IR for b-catenin only WNT tumors. IRs for filamin A and YAP1 identify SHH and WNT tumors. SHH, WNT, and non-SHH/WNT tumors contributed 31, 14, and 55% to the series. All desmoplastic/nodular (D/N) medulloblastomas were SHH tumors, while most WNT tumors (94%) had a classic phenotype. Monosomy 6 was strongly associated with WNT tumors, while PTCH1 loss occurred almost exclusively among SHH tumors. MYC or MYCN amplification and chromosome 17 imbalance occurred predominantly among non-SHH/WNT tumors. Among patients aged 3-16 years Electronic supplementary material The online version of this article (and entered onto the SIOP PNET3 trial, outcome was significantly better for children with WNT tumors, when compared to SHH or non-SHH/WNT tumors, which showed similar survival curves. However, high-risk factors (M? disease, LC/A pathology, MYC amplification) significantly influenced survival in both SHH and non-SHH/WNT groups. We describe a robust method for detecting SHH, WNT, and non-SHH/WNT molecular subgroups in formalin-fixed medulloblastoma samples. In corroborating other studies that indicate the value of combining clinical, pathological, and molecular variables in therapeutic stratification schemes for medulloblastoma, we also provide the first outcome data based on a clinical trial cohort and novel data on how molecular subgroups are distributed across the range of disease.
Identification ofPATCHED mutations in medulloblastomas by direct sequencing
Human Mutation, 2000
Communicated by Mark H. Paalman Medulloblastoma is the most common malignant embryonic tumors of the central nervous system. The nevoid basal cell carcinoma syndrome (NBCCS), which is caused by mutations of PTCH gene on chromosome 9q22, accounts for about 2% of all medulloblastomas. Previous studies of PTCH in sporadic medulloblastomas using single strand conformational polymorphism (SSCP) detected mutations in about 10% of the tumors. In this study, we directly sequenced the PTCH gene in 20 sporadic medulloblastoma DNA samples. A nonsense mutation (Q694X) and a splice site alteration (2875+1G>A) were identified in two of the samples. The mutations are predicted to result in a truncated PTCH protein and aberrant splicing, respectively. In both cases, only the mutant alleles were identified, indicating that the mutations were associated with loss of the wild-type PTCH allele in the tumor cells. Several novel variants, including 1653T>C, 1672C>T, and 2292C>T, were also found in these tumor samples. One of the two mutations detected in this study had been missed by SSCP, suggesting that the true rate of PTCH mutations in sporadic medulloblastomas may be underestimated by SSCP screening. Nevertheless, the frequency of mutations in this study did not differ from previous reports.
Acta Neuropathologica, 2012
Medulloblastoma is the most common malignant brain tumor in childhood. Molecular studies from several groups around the world demonstrated that medulloblastoma is not one disease but comprises a collection of distinct molecular subgroups. However, all these studies reported on different numbers of subgroups. The current consensus is that there are only four core subgroups, which should be termed WNT, SHH, Group 3 and Group 4. Based on this, we performed a meta-analysis of all molecular and clinical data of 550 medulloblastomas brought together from seven independent studies. All cases were analyzed by gene expression profiling and for most cases SNP or array-CGH data were available. Data are presented for all medulloblastomas together and for each subgroup separately. For validation purposes, we compared the results of this meta-analysis with another large Electronic supplementary material The online version of this article (
The Lancet Oncology
Background Most children with medulloblastoma fall within the standard-risk clinical disease group defined by absence of high-risk features (metastatic disease, large-cell/anaplastic histology, and MYC amplification), which includes 50-60% of patients and has a 5-year event-free survival of 75-85%. Within standard-risk medulloblastoma, patients in the WNT subgroup are established as having a favourable prognosis; however, outcome prediction for the remaining majority of patients is imprecise. We sought to identify novel prognostic biomarkers to enable improved risk-adapted therapies. Methods The HIT-SIOP PNET 4 trial recruited 338 patients aged 4-21 years with medulloblastoma between Jan 1, 2001, and Dec 31, 2006, in 120 treatment institutions in seven European countries to investigate hyperfractionated radiotherapy versus standard radiotherapy. In this retrospective analysis, we assessed the remaining tumour samples from patients in the HIT-SIOP PNET 4 trial (n=136). We assessed the clinical behaviour of the molecularly defined WNT and SHH subgroups, and identified novel independent prognostic markers and models for standard-risk patients with non-WNT/non-SHH disease. Because of the scarcity and low quality of available genomic material, we used a mass spectrometry-minimal methylation classifier assay (MS-MIMIC) to assess methylation subgroup and a molecular inversion probe array to detect genome-wide copy number aberrations. Prognostic biomarkers and models identified were validated in an independent, demographically matched cohort (n=70) of medulloblastoma patients with non-WNT/non-SHH standard-risk disease treated with conventional therapies (maximal surgical resection followed by adjuvant craniospinal irradiation [all patients] and chemotherapy [65 of 70 patients], at UK Children's Cancer and Leukaemia Group and European Society for Paediatric Oncology (SIOPE) associated treatment centres between 1990 and 2014. These samples were analysed by Illumina 450k DNA methylation microarray. HIT-SIOP PNET 4 is registered with ClinicalTrials.gov, number NCT01351870. Findings We analysed methylation subgroup, genome-wide copy number aberrations, and mutational features in 136 assessable tumour samples from the HIT-SIOP PNET 4 cohort, representing 40% of the 338 patients in the trial cohort. This cohort of 136 samples consisted of 28 (21%) classified as WNT, 17 (13%) as SHH, and 91 (67%) as non-WNT/non-SHH (we considered Group3 and Group4 medulloblastoma together in our analysis because of their similar molecular and clinical features). Favourable outcomes for WNT tumours were confirmed in patients younger than 16 years, and all relapse events in SHH (four [24%] of 17) occurred in patients with TP53 mutation (TP53 mut) or chromosome 17p loss. A novel whole chromosomal aberration signature associated with increased ploidy and multiple non-random whole chromosomal aberrations was identified in 38 (42%) of the 91 samples from patients with non-WNT/non-SHH medulloblastoma in the HIT-SIOP PNET 4 cohort. Biomarkers associated with this whole chromosomal aberration signature (at least two of chromosome 7 gain, chromosome 8 loss, and chromosome 11 loss) predicted favourable prognosis. Patients with non-WNT/non-SHH medulloblastoma could be reclassified by these markers as having favourable-risk or high-risk disease. In patients in the HIT-SIOP PNET4 cohort with non-WNT/ non-SHH medulloblastoma, with a median follow-up of 6•7 years (IQR 5•8-8•2), 5-year event-free survival was 100% in the favourable-risk group and 68% (95% CI 57•5-82•7; p=0•00014) in the high-risk group. In the validation cohort, with a median follow-up of 5•6 years (IQR 3•1-8•1), 5-year event-free survival was 94•7% (95% CI 85•2-100) in the favourable-risk group and 58•6% (95% CI 45•1-76•1) in the high-risk group (hazard ratio 9•41, 95% CI 1•25-70•57; p=0•029). Our comprehensive molecular investigation identified subgroup-specific risk models which allowed 69 (51%) of 134 accessible patients from the standard-risk medulloblastoma HIT-SIOP PNET 4 cohort to be assigned to a favourable-risk group. Interpretation We define a whole chromosomal signature that allows the assignment of non-WNT/non-SHH medulloblastoma patients normally classified as standard-risk into favourable-risk and high-risk categories. In addition to patients younger than 16 years with WNT tumours, patients with non-WNT/non-SHH tumours with our
Rapid Diagnosis of Medulloblastoma Molecular Subgroups
Clinical Cancer Research, 2011
Purpose: Microarray studies indicate medulloblastoma comprises distinct molecular disease subgroups, which offer potential for improved clinical management. Experimental Design: Minimal mRNA expression signatures diagnostic for the Wnt/Wingless (WNT) and Sonic Hedgehog (SHH) subgroups were developed, validated, and used to assign subgroup affiliation in 173 tumors from four independent cohorts, alongside a systematic investigation of subgroup clinical and molecular characteristics. Results: WNT tumors [12% (21/173)] were diagnosed >5 years of age (peak, 10 years), displayed classic histology, CTNNB1 mutation (19/20), and associated chromosome 6 loss, and have previously been associated with favorable prognosis. SHH cases [24% (42/173)] predominated in infants (<3 years) and showed an age-dependent relationship to desmoplastic/nodular pathology; all infant desmoplastic/ nodular cases (previously associated with a good outcome) were SHH-positive, but these relationships broke down in noninfants. PTCH1 mutations were common [34% (11/32)], but PTCH1 exon1c hypermethylation, chromosome 9q and REN (KCTD11) genetic loss were not SHH associated, and SMO or SUFU mutation, PTCH1 exon1a or SUFU hypermethylation did not play a role, indicating novel activating mechanisms in the majority of SHH cases. SHH tumors were associated with an absence of COL1A2 methylation. WNT/SHH-independent medulloblastomas [64% (110/173)] showed all histologies, peaked at 3 and 6 years, and were exclusively associated with chromosome 17p loss. Conclusions: Medulloblastoma subgroups are characterized by distinct genomic, epigenomic and clinicopathologic features, and clinical outcomes. Validated array-independent gene expression assays for the rapid assessment of subgroup affiliation in small biopsies provide a basis for their routine clinical application, in strategies including molecular disease-risk stratification and delivery of targeted therapeutics. Clin Cancer Res; 17(7); 1883-94. Ó2011 AACR.
Subgroup-Specific Prognostic Implications of TP53 Mutation in Medulloblastoma
Journal of Clinical Oncology, 2013
Purpose Reports detailing the prognostic impact of TP53 mutations in medulloblastoma offer conflicting conclusions. We resolve this issue through the inclusion of molecular subgroup profiles. Patients and Methods We determined subgroup affiliation, TP53 mutation status, and clinical outcome in a discovery cohort of 397 medulloblastomas. We subsequently validated our results on an independent cohort of 156 medulloblastomas. Results TP53 mutations are enriched in wingless (WNT; 16%) and sonic hedgehog (SHH; 21%) medulloblastomas and are virtually absent in subgroups 3 and 4 tumors (P < .001). Patients with SHH/TP53 mutant tumors are almost exclusively between ages 5 and 18 years, dramatically different from the general SHH distribution (P < .001). Children with SHH/TP53 mutant tumors harbor 56% germline TP53 mutations, which are not observed in children with WNT/TP53 mutant tumors. Five-year overall survival (OS; ± SE) was 41% ± 9% and 81% ± 5% for patients with SHH medulloblast...