| 1. |
- Campbell, Brittany B., et al.
(författare)
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Comprehensive Analysis of Hypermutation in Human Cancer
- 2017
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Ingår i: Cell. - : Elsevier BV. - 0092-8674 .- 1097-4172. ; 171:5
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Tidskriftsartikel (refereegranskat)abstract
- © 2017 Elsevier Inc. We present an extensive assessment of mutation burden through sequencing analysis of > 81,000 tumors from pediatric and adult patients, including tumors with hypermutation caused by chemotherapy, carcinogens, or germline alterations. Hypermutation was detected in tumor types not previously associated with high mutation burden. Replication repair deficiency was a major contributing factor. We uncovered new driver mutations in the replication-repair-associated DNA polymerases and a distinct impact of microsatellite instability and replication repair deficiency on the scale of mutation load. Unbiased clustering, based on mutational context, revealed clinically relevant subgroups regardless of the tumors' tissue of origin, highlighting similarities in evolutionary dynamics leading to hypermutation. Mutagens, such as UV light, were implicated in unexpected cancers, including sarcomas and lung tumors. The order of mutational signatures identified previous treatment and germline replication repair deficiency, which improved management of patients and families. These data will inform tumor classification, genetic testing, and clinical trial design. A large-scale analysis of hypermutation in human cancers provides insights into tumor evolution dynamics and identifies clinically actionable mutation signatures.
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| 2. |
- Das, Anirban, et al.
(författare)
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Combined immunotherapy improves outcome for replication repair deficient (RRD) high-grade glioma failing anti-PD1 monotherapy: A report from the International RRD Consortium.
- 2024
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Ingår i: Cancer discovery. - 2159-8290. ; 14:2, s. 258-273
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Tidskriftsartikel (refereegranskat)abstract
- Immune-checkpoint inhibition (ICI) is effective for replication-repair deficient, high-grade gliomas (RRD-HGG). Clinical/biologic impact of immune-directed approaches after failing ICI-monotherapy are unknown. We performed an international study on 75 patients treated with anti-PD1; 20 are progression-free (median follow-up: 3.7-years). After 2nd-progression/recurrence (n=55), continuing ICI-based salvage prolonged survival to 11.6-months (n=38; p<0.001), particularly for those with extreme mutation burden (p=0.03). Delayed, sustained responses were observed, associated with changes in mutational spectra and immune-microenvironment. Response to re-irradiation was explained by an absence of deleterious post-radiation indel signatures (ID8). Increased CTLA4-expression over time, and subsequent CTLA4-inhibition resulted in response/stable disease in 75%. RAS-MAPK-pathway inhibition led to reinvigoration of peripheral immune and radiological responses. Local (flare) and systemic immune adverse events were frequent (biallelic mismatch-repair deficiency > Lynch syndrome). We provide mechanistic rationale for the sustained benefit in RRD-HGG from immune-directed/ synergistic salvage therapies. Future approaches need to be tailored to patient and tumor biology.
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| 3. |
- Ercan, Ayse Bahar, et al.
(författare)
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Clinical and biological landscape of constitutional mismatch-repair deficiency syndrome: an International Replication Repair Deficiency Consortium cohort study.
- 2024
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Ingår i: The Lancet. Oncology. - 1474-5488. ; 25:5, s. 668-682
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Tidskriftsartikel (refereegranskat)abstract
- Constitutional mismatch repair deficiency (CMMRD) syndrome is a rare and aggressive cancer predisposition syndrome. Because a scarcity of data on this condition contributes to management challenges and poor outcomes, we aimed to describe the clinical spectrum, cancer biology, and impact of genetics on patient survival in CMMRD.In this cohort study, we collected cross-sectional and longitudinal data on all patients with CMMRD, with no age limits, registered with the International Replication Repair Deficiency Consortium (IRRDC) across more than 50 countries. Clinical data were extracted from the IRRDC database, medical records, and physician-completed case record forms. The primary objective was to describe the clinical features, cancer spectrum, and biology of the condition. Secondary objectives included estimations of cancer incidence and of the impact of the specific mismatch-repair gene and genotype on cancer onset and survival, including after cancer surveillance and immunotherapy interventions.We analysed data from 201 patients (103 males, 98 females) enrolled between June 5, 2007 and Sept 9, 2022. Median age at diagnosis of CMMRD or a related cancer was 8·9 years (IQR 5·9-12·6), and median follow-up from diagnosis was 7·2 years (3·6-14·8). Endogamy among minorities and closed communities contributed to high homozygosity within countries with low consanguinity. Frequent dermatological manifestations (117 [93%] of 126 patients with complete data) led to a clinical overlap with neurofibromatosis type 1 (35 [28%] of 126). 339 cancers were reported in 194 (97%) of 201 patients. The cumulative cancer incidence by age 18 years was 90% (95% CI 80-99). Median time between cancer diagnoses for patients with more than one cancer was 1·9 years (IQR 0·8-3·9). Neoplasms developed in 15 organs and included early-onset adult cancers. CNS tumours were the most frequent (173 [51%] cancers), followed by gastrointestinal (75 [22%]), haematological (61 [18%]), and other cancer types (30 [9%]). Patients with CNS tumours had the poorest overall survival rates (39% [95% CI 30-52] at 10 years from diagnosis; log-rank p<0·0001 across four cancer types), followed by those with haematological cancers (67% [55-82]), gastrointestinal cancers (89% [81-97]), and other solid tumours (96% [88-100]). All cancers showed high mutation and microsatellite indel burdens, and pathognomonic mutational signatures. MLH1 or MSH2 variants caused earlier cancer onset than PMS2 or MSH6 variants, and inferior survival (overall survival at age 15 years 63% [95% CI 55-73] for PMS2, 49% [35-68] for MSH6, 19% [6-66] for MLH1, and 0% for MSH2; p<0·0001). Frameshift or truncating variants within the same gene caused earlier cancers and inferior outcomes compared with missense variants (p<0·0001). The greater deleterious effects of MLH1 and MSH2 variants as compared with PMS2 and MSH6 variants persisted despite overall improvements in survival after surveillance or immune checkpoint inhibitor interventions.The very high cancer burden and unique genomic landscape of CMMRD highlight the benefit of comprehensive assays in timely diagnosis and precision approaches toward surveillance and immunotherapy. These data will guide the clinical management of children and patients who survive into adulthood with CMMRD.The Canadian Institutes for Health Research, Stand Up to Cancer, Children's Oncology Group National Cancer Institute Community Oncology Research Program, Canadian Cancer Society, Brain Canada, The V Foundation for Cancer Research, BioCanRx, Harry and Agnieszka Hall, Meagan's Walk, BRAINchild Canada, The LivWise Foundation, St Baldrick Foundation, Hold'em for Life, and Garron Family Cancer Center.
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| 4. |
- Mangerel, Joshua, et al.
(författare)
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Alternative lengthening of telomerases is enriched in, and impacts survival of TP53 mutant pediatric malignant brain tumors
- 2014
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Ingår i: Acta Neuropathologica. - : Springer Science and Business Media LLC. - 0001-6322 .- 1432-0533. ; 128:6, s. 853-862
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Tidskriftsartikel (refereegranskat)abstract
- Although telomeres are maintained in most cancers by telomerase activation, a subset of tumors utilize alternative lengthening of telomeres (ALT) to sustain self-renewal capacity. In order to study the prevalence and significance of ALT in childhood brain tumors we screened 517 pediatric brain tumors using the novel C-circle assay. We examined the association of ALT with alterations in genes found to segregate with specific histological phenotypes and with clinical outcome. ALT was detected almost exclusively in malignant tumors (p = 0.001). ALT was highly enriched in primitive neuroectodermal tumors (12 %), choroid plexus carcinomas (23 %) and high-grade gliomas (22 %). Furthermore, in contrast to adult gliomas, pediatric low grade gliomas which progressed to high-grade tumors did not exhibit the ALT phenotype. Somatic but not germline TP53 mutations were highly associated with ALT (p = 1.01 × 10(-8)). Of the other alterations examined, only ATRX point mutations and reduced expression were associated with the ALT phenotype (p = 0.0005). Interestingly, ALT attenuated the poor outcome conferred by TP53 mutations in specific pediatric brain tumors. Due to very poor prognosis, one year overall survival was quantified in malignant gliomas, while in children with choroid plexus carcinoma, five year overall survival was investigated. For children with TP53 mutant malignant gliomas, one year overall survival was 63 ± 12 and 23 ± 10 % for ALT positive and negative tumors, respectively (p = 0.03), while for children with TP53 mutant choroid plexus carcinomas, 5 years overall survival was 67 ± 19 and 27 ± 13 % for ALT positive and negative tumors, respectively (p = 0.07). These observations suggest that the presence of ALT is limited to a specific group of childhood brain cancers which harbor somatic TP53 mutations and may influence the outcome of these patients. Analysis of ALT may contribute to risk stratification and targeted therapies to improve outcome for these children.
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| 5. |
- Nobre, Liana, et al.
(författare)
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Outcomes of BRAF V600E pediatric gliomas treated with targeted BRAF inhibition
- 2020
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Ingår i: JCO Precision Oncology. - 2473-4284. ; 3, s. 561-571
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Tidskriftsartikel (refereegranskat)abstract
- © 2020 by American Society of Clinical Oncology PURPOSE Children with pediatric gliomas harboring a BRAF V600E mutation have poor outcomes with current chemoradiotherapy strategies. Our aim was to study the role of targeted BRAF inhibition in these tumors. PATIENTS AND METHODS We collected clinical, imaging, molecular, and outcome information from patients with BRAF V600E–mutated glioma treated with BRAF inhibition across 29 centers from multiple countries. RESULTS Sixty-seven patients were treated with BRAF inhibition (pediatric low-grade gliomas [PLGGs], n = 56; pediatric high-grade gliomas [PHGGs], n = 11) for up to 5.6 years. Objective responses were observed in 80% of PLGGs, compared with 28% observed with conventional chemotherapy (P, .001). These responses were rapid (median, 4 months) and sustained in 86% of tumors up to 5 years while receiving therapy. After discontinuation of BRAF inhibition, 76.5% (13 of 17) of patients with PLGG experienced rapid progression (median, 2.3 months). However, upon rechallenge with BRAF inhibition, 90% achieved an objective response. Poor prognostic factors in conventional therapies, such as concomitant homozygous deletion of CDKN2A, were not associated with lack of response to BRAF inhibition. In contrast, only 36% of those with PHGG responded to BRAF inhibition, with all but one tumor progressing within 18 months. In PLGG, responses translated to 3-year progression-free survival of 49.6% (95% CI, 35.3% to 69.5%) versus 29.8% (95% CI, 20% to 44.4%) for BRAF inhibition versus chemotherapy, respectively (P = .02). CONCLUSION Use of BRAF inhibition results in robust and durable responses in BRAF V600E–mutated PLGG. Prospective studies are required to determine long-term survival and functional outcomes with BRAF inhibitor therapy in childhood gliomas.
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| 6. |
- Zhukova, Nataliya, et al.
(författare)
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WNT activation by lithium abrogates TP53 mutation associated radiation resistance in medulloblastoma
- 2014
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Ingår i: Acta neuropathologica communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- TP53 mutations confer subgroup specific poor survival for children with medulloblastoma. We hypothesized that WNT activation which is associated with improved survival for such children abrogates TP53 related radioresistance and can be used to sensitize TP53 mutant tumors for radiation. We examined the subgroup-specific role of TP53 mutations in a cohort of 314 patients treated with radiation. TP53 wild-type or mutant human medulloblastoma cell-lines and normal neural stem cells were used to test radioresistance of TP53 mutations and the radiosensitizing effect of WNT activation on tumors and the developing brain. Children with WNT/TP53 mutant medulloblastoma had higher 5-year survival than those with SHH/TP53 mutant tumours (100% and 36.6%±8.7%, respectively (p<0.001)). Introduction of TP53 mutation into medulloblastoma cells induced radioresistance (survival fractions at 2Gy (SF2) of 89%±2% vs. 57.4%±1.8% (p<0.01)). In contrast, beta-catenin mutation sensitized TP53 mutant cells to radiation (p<0.05). Lithium, an activator of the WNT pathway, sensitized TP53 mutant medulloblastoma to radiation (SF2 of 43.5%±1.5% in lithium treated cells vs. 56.6±3% (p<0.01)) accompanied by increased number of gammaH2AX foci. Normal neural stem cells were protected from lithium induced radiation damage (SF2 of 33%±8% for lithium treated cells vs. 27%±3% for untreated controls (p=0.05). Poor survival of patients with TP53 mutant medulloblastoma may be related to radiation resistance. Since constitutive activation of the WNT pathway by lithium sensitizes TP53 mutant medulloblastoma cells and protect normal neural stem cells from radiation, this oral drug may represent an attractive novel therapy for high-risk medulloblastomas.
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