Citations

Abstract Most TERT promoter (TERTp) clinically relevant sequence variants in CNS tumors are the canonical C228T and C250T mutations. Non-canonical TERTp mutations have been reported mainly in non-CNS tumors. We describe 12 CNS tumors with non-canonical TERTp variants interpreted as clinically relevant. Using clinical targeted NGS panels (2020-2024), we detected c.-100_-79dup (n=2), c.-92_-91insGGCGGCCCCGCCCCTTCCTTTC (n=1), c.-118_-117insTCCCCGGCCCAGCCCCTTCCGGG (n=1), c.-123_-76dup (n=1), c.-110_-89dup (n=2), and c.-57A>C (n=5). Most cases had chromosomal microarray (n=11) and/or methylation array data analyzed using the NCI/Bethesda v.2 classifier (n=9). All non-canonical TERTp variants occurred at a variant allele frequency suggestive of somatic clonal origin (mean, 34%; range, 18-46), and in adults (mean age, 60 years; range, 36-88). Except for the c.-57A>C variant, all non-canonical TERTp variants occurred in tumors with histological and/or molecular diagnostic features of glioblastoma, IDH-wildtype (GBM), often epigenetically aligning to this tumor type. All five tested cases matched to superfamily glioblastoma (score ≥ 0.9), with three to class GBM_RTK_I (>0.9 in 2, 0.86 in 1) and two to GBM_RTK_II (>0.9). The size and sequence of such variants suggest that these may be functionally equivalent to canonical mutations or generate favorable TERTp activation motif conformations like previously reported activating duplications. The c.-57A>C variant is a well-established oncogenic mutation observed in other cancer types but has not been reported in CNS tumors. We describe five cases with the c.-57A>C variant: one GBM matching to methylation class GBM_MES_TYP (0.99); two oligodendroglioma, IDH-mutant and 1p/19q-codeleted, one of which had methylation data matching to class O_IDH (0.99); one diffuse glioma, IDH-mutant, which was partially 1p/19q-codeleted and matched to class O_IDH (0.99); and one anaplastic meningioma, aligning to superfamily meningioma (0.99)/MNG_MAL (0.79). Our findings show that non-canonical TERTp variants typically occur in tumor types that often harbor TERTp canonical mutations, expanding the spectrum of TERTp clinically relevant variants that are molecular biomarkers in CNS tumors.

Abstract TP53 mutations are frequent in IDH-mutant astrocytomas but unusual in oligodendroglioma and the clinical significance of TP53 mutations in oligodendroglioma are not well characterized. We reviewed genetically defined oligodendroglioma (i.e., IDH-mutant, whole-arm 1p/19q-codeleted diffuse glioma) cases that were molecularly profiled (2017-2020) at our institution and identified 7 cases with TP53 mutation (9%; n=76). Molecular testing was performed using targeted neuro-oncology NGS panel (50-gene mutation and/or 187-gene mutation/rearrangement) and OncoScan™ microarray. Four (of 7) patients were female. Median age at diagnosis was 43 years (range, 23-63). Most common presenting symptom was seizures (3 of 7). All tumors were supratentorial. Histologically, 3 tumors were WHO grade II and 4 were WHO grade III. Two (of 3) patients with a WHO grade II tumor underwent biopsy and radiotherapy at diagnosis followed by temozolomide at recurrence (progression at 67 and 157 months after diagnosis; overall survival of 124 and 201 months). Three (of 4) patients with a WHO grade III tumor were diagnosed within the last two years and are currently progression-free after standard therapy. Molecularly, in addition to TP53 mutation(s), all cases had an IDH1 and TERT promoter mutation as well as other gene mutation(s) including FUBP1 (n=5), SETD2 (n=4), PIK3R1 (n=4), PIK3CA (n=3), NF1 (n=3) and CIC (n=3). In 3 (of 7) cases, the mutational profile with high mutation count enriched for C >T/G >A transitions was highly suggestive of a hypermutation phenotype (2 cases were recurrent tumors treated with temozolomide; a recurrent and a treatment-naïve tumor had mismatch repair gene mutation). Five (of 7) cases, including the 3 hypermutant cases, lacked functional TP53 (1 case with 2 mutations, 2 cases with 1 mutation plus loss of other copy, 2 cases with 1 mutation plus copy neutral loss-of-heterozygosity). TP53 mutations are uncommon in oligodendroglioma and appear enriched in hypermutant tumors.

Abstract Polymorphous low-grade neuroepithelial tumor of the young (PLNTY) is a recently described epileptogenic tumor characterized by oligodendroglioma-like components, aberrant CD34 expression, and frequent mitogen-activated protein kinase (MAPK) pathway activation. We molecularly profiled 13 cases with diagnostic histopathological features of PLNTY (10 female; median age, 16 years; range, 5–52). Patients frequently presented with seizures (9 of 12 with available history) and temporal lobe tumors (9 of 13). MAPK pathway activating alterations were identified in all 13 cases. Fusions were present in the 7 youngest patients: FGFR2-CTNNA3 (n = 2), FGFR2-KIAA1598 (FGFR2-SHTN1) (n = 1), FGFR2-INA (n = 1), FGFR2-MPRIP (n = 1), QKI-NTRK2 (n = 1), and KIAA1549-BRAF (n = 1). BRAF V600E mutation was present in 6 patients (17 years or older). Two fusion-positive cases additionally harbored TP53/RB1 abnormalities suggesting biallelic inactivation. Copy number changes predominantly involving whole chromosomes were observed in all 10 evaluated cases, with losses of chromosome 10q occurring with FGFR2-KIAA1598 (SHTN1)/CTNNA3 fusions. The KIAA1549-BRAF and QKI-NTRK2 fusions were associated respectively with a 7q34 deletion and 9q21 duplication. This study shows that despite its name, PLNTY also occurs in older adults, who frequently show BRAF V600E mutation. It also expands the spectrum of the MAPK pathway activating alterations associated with PLNTY and demonstrates recurrent chromosomal copy number changes consistent with chromosomal instability.

Abstract Purpose: ZIP4 is overexpressed in human pancreatic cancer and promotes tumor growth. However, little is known about the role of ZIP4 in advanced stages of this dismal neoplasm. Our goal is to study the underlying mechanism and define a novel signaling pathway controlled by ZIP4-modulating pancreatic tumor metastasis. Experimental Design: The expression of ZIP4, ZO-1, claudin-1, and ZEB1 in human pancreatic cancer tissues, genetically engineered mouse model, xenograft tumor model, and pancreatic cancer cell lines were examined, and the correlations between ZIP4 and those markers were also analyzed. Functional analysis of ZO-1, claudin-1, and ZEB1 was investigated in pancreatic cancer cell lines and orthotopic xenografts. Results: Genetic inactivation of ZIP4 inhibited migration and invasion in pancreatic cancer and increased the expression of ZO-1 and claudin-1. Conversely, overexpression of ZIP4 promoted migration and invasion and increased the expression of ZEB1 and downregulation of the aforementioned epithelial genes. ZIP4 downregulation of ZO-1 and claudin-1 requires the transcriptional repressor ZEB1. Further analysis demonstrated that ZIP4-mediated repression of ZO-1 and claudin-1 leads to upregulation of their targets FAK and Paxillin. Silencing of ZIP4 caused reduced phosphorylation of FAK and Paxillin, which was rescued by simultaneous blocking of ZO-1 or claudin-1. Clinically, we demonstrated that ZIP4 positively correlates with the levels of ZEB1 and inversely associates with the expression of ZO-1 and claudin-1. Conclusions: These findings suggest a novel pathway activated by ZIP4-controlling pancreatic cancer invasiveness and metastasis, which could serve as a new therapeutic target for this devastating disease. Clin Cancer Res; 24(13); 3186–96. ©2018 AACR.

Abstract TARGET POPULATION Adults diagnosed with vestibular schwannomas. QUESTION 1 What is the prognostic significance of Antoni A vs B histologic patterns in vestibular schwannomas? RECOMMENDATION No recommendations can be made due to a lack of adequate data. QUESTION 2 What is the prognostic significance of mitotic figures seen in vestibular schwannoma specimens? RECOMMENDATION No recommendations can be made due to a lack of adequate data. QUESTION 3 Are there other light microscopic features that predict clinical behavior of vestibular schwannomas? RECOMMENDATION No recommendations can be made due to a lack of adequate data. QUESTION 4 Does the KI-67 labeling index predict clinical behavior of vestibular schwannomas? RECOMMENDATION No recommendations can be made due to a lack of adequate data. QUESTION 5 Does the proliferating cell nuclear antigen labeling index predict clinical behavior of vestibular schwannomas? RECOMMENDATION No recommendations can be made due to a lack of adequate data. QUESTION 6 Does degree of vascular endothelial growth factor expression predict clinical behavior of vestibular schwannomas? RECOMMENDATION No recommendations can be made due to a lack of adequate data. The full guideline can be found at: https://www.cns.org/guidelines/guidelines-management-patients-vestibular-schwannoma/chapter_6.

Abstract Background Thyroid carcinoma, which is rare in pediatric patients (age 0–18 years) but more common in adolescent and young adult (AYA) patients (age 15–39 years), carries the potential for morbidity and mortality. Methods Hybrid-capture-based comprehensive genomic profiling (CGP) was performed prospectively on 512 consecutively submitted thyroid carcinomas, including 58 from pediatric and AYA (PAYA) patients, to identify genomic alterations (GAs), including base substitutions, insertions/deletions, copy number alterations, and rearrangements. This PAYA data series includes 41 patients with papillary thyroid carcinoma (PTC), 3 with anaplastic thyroid carcinoma (ATC), and 14 with medullary thyroid carcinoma (MTC). Results GAs were detected in 93% (54/58) of PAYA cases, with a mean of 1.4 GAs per case. In addition to BRAF V600E mutations, detected in 46% (19/41) of PAYA PTC cases and in 1 of 3 AYA ATC cases, oncogenic fusions involving RET, NTRK1, NTRK3, and ALK were detected in 37% (15/41) of PAYA PTC and 33% (1/3) of AYA ATC cases. Ninety-three percent (13/14) of MTC patients harbored RET alterations, including 3 novel insertions/deletions in exons 6 and 11. Two of these MTC patients with novel alterations in RET experienced clinical benefit from vandetanib treatment. Conclusion CGP identified diverse clinically relevant GAs in PAYA patients with thyroid carcinoma, including 83% (34/41) of PTC cases harboring activating kinase mutations or activating kinase rearrangements. These genomic observations and index cases exhibiting clinical benefit from targeted therapy suggest that young patients with advanced thyroid carcinoma can benefit from CGP and rationally matched targeted therapy.