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Paper 4
Published in Amanda Rabone, Benedict Thomson, Nicky Dineen, Vincent Helyar, Aidan Shaw, The Final FRCR, 2020
Amanda Rabone, Benedict Thomson, Nicky Dineen, Vincent Helyar, Aidan Shaw
Turcot syndrome is characterised by colon cancer as well as primary brain tumours, such as glioblastoma and medulloblastoma. Although the father in this case died from glioblastoma, Turcot syndrome is rare compared to Lynch syndrome.
Pediatric Central Nervous System Tumors as Phenotypic Manifestation of Cancer Predisposition Syndromes
Published in David A. Walker, Giorgio Perilongo, Roger E. Taylor, Ian F. Pollack, Brain and Spinal Tumors of Childhood, 2020
Giorgio Perilongo, Irene Toldo, Stefano Sartori
A de-escalation of the conventional chemotherapy and craniospinal radiotherapy approach is presently under consideration for this subgroup of medulloblastoma. The immunohistochemistry marker of WNT involvement in medulloblastoma is the nuclear accumulation of the β-catenin, a gene product that if entering the nucleus activates a cascade of other genes which ultimately promote cell proliferation. Almost all medulloblastomas belonging to the WNT group present positive nuclear staining for β-catenin. In total, 70–80% of this subtype of medulloblastoma present also with monosomy 6. It is indeed a minority of them which bears the APC mutation. Only the WNT genetic signature of the tumor can imply the diagnosis of Turcot syndrome, which must then be confirmed by the presence of an APC gene abnormality. It is of paramount importance to identify these rare patients affected by Turcot type 2 syndrome in order to enroll them in the appropriate screening program for colon cancer.16
Constitutional Mismatch Repair Deficiency Syndrome
Published in Dongyou Liu, Handbook of Tumor Syndromes, 2020
Turcot syndrome may be separated into two types. Accounting for 33% of cases, Turcot syndrome type 1 is an autosomal recessive disorder attributed to homozygous or compound heterozygous germline-inactivating mutations in DNA mismatch repair genes MLH1 and PMS2, with increased risk for brain tumor (e.g., glioma), colorectal adenomas, and relatively few colonic polyps. Representing 67% of cases, Turcot syndrome type 2 is an autosomal dominant disorder linked to heterozygous germline inactivating mutations in familial adenomatous polyposis (FAP) gene (see Chapter 16 in this volume), with increased risk for multiple colonic polyps, colorectal cancer, and brain tumor (e.g., medulloblastoma) [2].
Multimodal imaging characteristics of congenital grouped hyper‐ and hypo‐pigmented fundus lesions
Published in Clinical and Experimental Optometry, 2020
Henrietta Wang, Angelica Ly, Michael Yapp, Nagi Assaad, Michael Kalloniatis
Being able to differentiate CGP‐RPE and its variants from other fundus lesions is clinically important. Although some conditions are benign and non‐progressive, others with a similar presentation can be sight‐ or life‐threatening and hence require a timely diagnosis.2007 For example, pigmented ocular fundus lesions (POFLs) which are often small pigmented lesions, usually oval in shape with a posterior tail,2005 typically appear in a cluster and hence may be difficult to differentiate from CGP‐RPE. However, the presence of these lesions has been linked to malignant conditions such as Gardner's syndrome, familial adenomatous polyposis and Turcot syndrome2015 and require timely diagnosis due to high mortality rates.2009 Although difficult to differentiate by funduscopy alone, multimodal imaging may be useful as a diagnostic aid. A previous study has shown benefit of using multimodal imaging as an adjunct to funduscopic examination and has shown it to reduce misdiagnosis rates of pigmented lesions such as choroidal melanomas.1990
Clinical and pre-clinical utility of genomics in medulloblastoma
Published in Expert Review of Neurotherapeutics, 2018
WNT tumors are defined by transcriptional activation in the WNT pathway, with almost 90% of cases harboring activating somatic mutations in exon 3 of beta-catenin (CTNNB1) [16]. Monosomy 6 is the only recurrent somatic copy number aberration and is observed in 75–80% of cases. Other mutations observed in WNT included DDX3X in 15–20%, TP53 in 10–15%, subunits of the SWI/SNF nucleosome remodeling complex in 33%, CSNK2B in 14%, and EPHA7 in 8%. TP53 mutations, although very prognostic in SHH patients, have no prognostic implications in WNT patients [17]. A small but important subset of patients will have pathogenic germline variants in Adenomatous polyposis coli (APC), consistent with Turcot syndrome and should be evaluated in all patients who do not harbor mutations in CTNNB1 [16,18].
Adult medulloblastoma: an overview on current and future strategies of treatment
Published in Expert Opinion on Orphan Drugs, 2019
Michele Antonio Capozza, Giovanna Trombatore, Silvia Triarico, Stefano Mastrangelo, Giorgio Attinà, Palma Maurizi, Antonio Ruggiero
WNT MB subgroup is mostly represented by classic MB. It occurs in patients aged between 5 and 25 years [6] and has a better overall survival (OS) than the other molecular group [15]. WNT pathway is generally activated by beta-catenin mutation and less frequently CREEBBP or SMARCA4 mutations [16]. In Turcot Syndrome, which is a hereditary syndrome characterized by intestinal polyposis and an increased incidence of MB, the WNT-pathway is activated by loss-of-function mutation of the Adenomatous Polyposis Coli (APC) gene mutation [17]. Lastly, sometimes WNT MB may present the monosomy of chromosome 6 or TP53 mutation, but in this case the presence of somatic TP53 mutation does not correlate with a worse prognosis [9].