Targeted next-generation sequencing of adult gliomas for retrospective prognostic evaluation and up-front diagnostics

AIMS

We aimed to reclassify a population-based cohort of 529 adult glioma patients to evaluate the prognostic impact of the 2016 World Health Organization (WHO) central nervous system tumour classification. Moreover, we evaluated the feasibility of gene panel next-generation sequencing (NGS) in daily diagnostics of 225 prospective glioma patients.

METHODS

The retrospective cohort was reclassified according to WHO 2016 criteria by immunohistochemistry for IDH-R132H, fluorescence in situ hybridization for 1p/19q-codeletion and gene panel NGS. All tumours of the prospective cohort were subjected to NGS analysis up-front.

RESULTS

The entire population-based cohort was successfully reclassified according to WHO 2016 criteria. NGS results were obtained for 98% of the prospective patients. Survival analyses in the population-based cohort confirmed three major prognostic subgroups, that is, isocitrate dehydrogenase (IDH)-mutant and 1p/19q-codeleted oligodendrogliomas, IDH-mutant astrocytomas and IDH-wildtype glioblastomas. The distinction between WHO grade II and III was prognostic in patients with IDH-mutant astrocytoma. The survival of patients with IDH-wildtype diffuse astrocytomas carrying TERT promoter mutation and/or EGFR amplification overlapped with the poor survival of IDH-wildtype glioblastoma patients.

CONCLUSIONS

Gene panel NGS proved feasible in daily diagnostics. In addition, our study confirms the prognostic role of glioma classification according to WHO 2016 in a large population-based cohort. Molecular features of glioblastoma in IDH-wildtype diffuse glioma were linked to poor survival corresponding to IDH-wildtype glioblastoma patients. The distinction between WHO grade II and III retained prognostic significance in patients with IDH-mutant diffuse astrocytic gliomas.

Brain tumour diagnostics using a DNA methylation-based classifier as a diagnostic support tool

AIMS

Methylation profiling (MP) is increasingly incorporated in the diagnostic process of central nervous system (CNS) tumours at our centres in The Netherlands and Scandinavia. We aimed to identify the benefits and challenges of MP as a support tool for CNS tumour diagnostics.

METHODS

About 502 CNS tumour samples were analysed using (850 k) MP. Profiles were matched with the DKFZ/Heidelberg CNS Tumour Classifier. For each case, the final pathological diagnosis was compared to the diagnosis before MP.

RESULTS

In 54.4% (273/502) of all analysed cases, the suggested methylation class (calibrated score ≥0.9) corresponded with the initial pathological diagnosis. The diagnosis of 24.5% of these cases (67/273) was more refined after incorporation of the MP result. In 9.8% of cases (49/502), the MP result led to a new diagnosis, resulting in an altered WHO grade in 71.4% of these cases (35/49). In 1% of cases (5/502), the suggested class based on MP was initially disregarded/interpreted as misleading, but in retrospect, the MP result predicted the right diagnosis for three of these cases. In six cases, the suggested class was interpreted as 'discrepant but noncontributory'. The remaining 33.7% of cases (169/502) had a calibrated score <0.9, including 7.8% (39/502) for which no class indication was given at all (calibrated score <0.3).

CONCLUSIONS

MP is a powerful tool to confirm and fine-tune the pathological diagnosis of CNS tumours, and to avoid misdiagnoses. However, it is crucial to interpret the results in the context of clinical, radiological, histopathological and other molecular information.

Low ANXA10 expression is associated with disease aggressiveness in bladder cancer

Background:

Markers for outcome prediction in bladder cancer are urgently needed. We have previously identified a molecular signature for predicting progression in non-muscle-invasive bladder cancer. ANXA10 was one of the markers included in the signature and we now validated the prognostic relevance of ANXA10 at the protein level.

Methods:

We investigated ANXA10 expression by immunohistochemistry using a tissue microarray with 249 Ta and T1 urothelial carcinomas. The expression of ANXA10 was also investigated in an additional set of 97 more advanced tumours. The functional role of ANXA10 in cell lines was investigated by siRNA-mediated ANXA10 knockdown using wound-healing assays, proliferation assays, and ingenuity pathway analysis.

Results:

Low expression of ANXA10 correlated with shorter progression-free survival in patients with stage Ta and T1 tumours (P<0.00001). Furthermore, patients with more advanced tumours and low ANXA10 expression had an unfavourable prognosis (P<0.00001). We found that ANXA10 siRNA transfected cells grew significantly faster compared with control siRNA transfected cells. Furthermore, a wound-healing assay showed that ANXA10 siRNA transfected cells spread along wound edges faster than control transfected cells.

Conclusion:

We conclude that ANXA10 may be a clinical relevant marker for predicting outcome in both early and advanced stages of bladder cancer.

Neuronal features of oligodendrogliomas--an ultrastructural and immunohistochemical study

AIMS

To assess neuronal differentiation in oligodendrogliomas (ODGs).

METHODS AND RESULTS

An electron microscopic and immunohistochemical study of 41 consecutive cases was performed. In all cases, tumour cells with neuritic structures were identified ultrastructurally, including synapses and neurosecretory granules. For the immunohistochemical identification of synaptophysin, monoclonal antibody clones 27G12, Snp88 and SY38 and a polyclonal antibody were compared in optimized protocols on slides from a spectrum of tissues and 16 ODGs. 27G12 gave the best signal-to-noise ratio, while SY38 gave the poorest. When 27G12 was applied on all 41 ODGs, widespread immunoreactivity was obtained in 100%. Among three antibodies to chromogranin compared similarly, clone LK2H10 and a polyclonal antibody gave identical patterns of immunoreactivity, whereas clone DAK-A3 gave weaker reactions. When LK2H10 was applied on all tumours, staining was found in 12 (29%). All tumours but one stained strongly for glial fibrillary acidic protein and all for synapsin I. Fluorescence in situ hybridization analysis showed a concomitant 1p/19q deletion in 12/16 ODGs.

CONCLUSIONS

Our study provides evidence for widespread neuronal differentiation in ODGs, suggesting that these tumours may be derived from progenitor cells with limited commitment. Antibody selection and protocol optimization are mandatory for reliable immunohistochemistry results.

[Intraspinal melanocytoma in a 16-year old girl]

Meningeal melanocytomas are rare benign neoplasms of meningeal melanocytes, and are most frequently located in the posterior fossa and along the cervical spinal cord. We report a case of a 16 year-old girl with a melanocytoma located in the upper cervical part of the spinal canal. The patient presented severe neurological signs, but had a very good outcome following surgery.

[Treatment of radiation-induced vesicovaginal fistula]

The records of 23 patients with vesicovaginal fistulae (VVF) probably caused by irradiation treatment for cancer of the uterine cervix were analyzed. The median latency between irradiation and fistula formation was 17 years. Ten patients had histologically verified cancer recurrence besides a VVF. In addition, nine patients had a rectovaginal- and one an ileovaginal fistula. Twelve patients were treated primarily with ureteroileocutaneostomy a.m. Bricker. Six had bladder drainage, and four of these had ureteroileocutaneostomy performed at a later stage. Four patients initially underwent percutaneous nephrostomy. One patients had a unilateral ureteroileocutaneostomy performed. Eight patients are alive today (median observation time 2.5 years), and all of these had had ureteroileocutaneostomy performed. Three of these patients (38%) were completely relieved of symptoms while the rest occasionally experienced pain, vaginal discharge and bladder empyema. We conclude that ureteroilocutaneostomy a.m. Bricker is a satisfactory procedure for vesicovaginal fistulae because the socially incapacitating symptoms disappear or are considerably diminished.