ALK Protein Expression Is Related to Neuroblastoma Aggressiveness But Is Not Independent Prognostic Factor

Multi-omics revealed that ELAVL3 regulates MYCN in neuroblastoma via immunogenic cell death: Risk stratification and experimental research

Neuroblastoma (NB), a common and highly lethal malignant disease in pediatrics, still lacks an effective therapeutic approach that addresses all conditions. Immunogenic Cell Death (ICD) plays a crucial role in tumor cell death and triggers a potent anti-tumor immune response. In this study, we report an ICD-related index (ICDR-Index) in NB through various machine learning methodologies, utilizing bulk transcriptome data from 1244 NB samples and 16 scRNA-seq datasets. Our results showed that the ICDR-Index could accurately identify different risk subtypes of patients with NB and provide predictive value for prognosis. Importantly, we found that high-risk patients with NB exhibited significantly poor overall survival (OS) rates, adverse clinical phenotypes, poor immune cell infiltration, and low sensitivity to immunotherapy. Furthermore, we identified ELAVL3 as a key gene within the ICDR-Index, where high expression levels were associated with malignancy and poor OS in NB. Additionally, targeted silencing of ELAVL3 down-regulated MYCN gene expression and reduced the malignancy of NB cells. Notably, the si-ELAVL3-transfected NB cells enhanced the anti-tumor activity of NK cells. Collectively, this study offers avenues for predicting the risk stratification of patients with NB and reveals a potential mechanism by which ELAVL3 regulates NB cell death.

Immunohistochemical expression of anaplastic lymphoma kinase in neuroblastoma and its relations with some clinical and histopathological features

BACKGROUND

Anaplastic lymphoma kinase (ALK) mutations have been identified as a prominent cause of some familial and sporadic neuroblastoma (NB). ALK expression in NB and its relationship with clinical and histopathological features remains controversial. This study investigated ALK expression and its potential relations with these features in NB.

METHODS

Ninety cases of NB at the Department of Pathology, University of Medicine and Pharmacy at Ho Chi Minh City, Viet Nam from 01/01/2018 to 12/31/2021, were immunohistochemically stained with ALK (D5F3) antibody. The ALK expression and its relations with some clinical and histopathological features were investigated.

RESULTS

The rate of ALK expression in NB was 91.1%. High ALK expression (over 50% of tumor cells were positive with moderate-strong intensity) accounted for 65.6%, and low ALK expression accounted for 34.4%. All the MYCN-amplified NB patients had ALK immunohistochemistry positivity, most cases had high ALK protein expression. The undifferentiated subtype of NB had a lower ALK-positive rate than the poorly differentiated and differentiated subtype. The percentages of ALK positivity were significantly higher in more differentiated histological types of NB (p = .024). There was no relation between ALK expression and: age group, sex, primary tumor location, tumor stage, MYCN status, clinical risk, Mitotic-Karyorrhectic Index, prognostic group, necrosis, and calcification.

CONCLUSIONS

ALK was highly expressed in NB. ALK expression was not related to several clinical and histopathological features. More studies are needed to elucidate the association between ALK expression and ALK gene status and to investigate disease progression, especially the oncogenesis of ALK-positive NB.

Rapid detection of telomerase expression of neuroblastoma in paraffin-embedded tissue: combination of in situ hybridisation and quantitative PCR

Neuroblastoma is a heterogeneous paediatric malignant tumour. Telomere maintenance mechanism (TMM) by telomerase activation or alternative lengthening of telomeres (ALT) is a hallmark of high-risk neuroblastoma. However, the prior assays for telomerase, such as TERT expression by RNA sequencing or microarrays, may not be easy to perform in many histopathology laboratories in hospitals. The aims of this study are to assess the utility of ultrasensitive single-cell RNA in situ hybridisation (RNAscope), immunohistochemistry, and RT-qPCR on formalin-fixed, paraffin-embedded tumour samples as diagnostic tools for detecting TERT expression in neuroblastoma. In this study, we detected MYCN amplification in 22 of 222 cases (10%), TERT rearrangements in 18 of 220 cases (8%), and ALT activation in 39 of 222 cases (18%) using fluorescence in situ hybridisation (FISH). By RNA in situ hybridisation, 36 of 210 (17%) pretreatment neuroblastomas were found to have TERT overexpression, which was significantly associated with the high-risk group (33/78, 42%), TERT rearrangements (16/18, 89%), and MYCN amplification (13/22, 59%). None of the tumours with ALT showed TERT staining. In our study, 19 of the 55 MYCN non-amplified high-risk neuroblastomas displayed TERT mRNA expression, including 13 of the 14 TERT rearrangements, none of the 30 ALT-positive cases, and a significant proportion (6/11, 55%) that did not have the aforementioned genomic anomalies. RT-qPCR results correlated well with RNAscope levels (Spearman's rho=0.621, p<0.001, n=94). In conclusion, TERT RNA in situ hybridisation and RT-qPCR are suitable methods to evaluate TERT expression in neuroblastoma. The combination of detection of the genomic alterations and TERT mRNA expression is a powerful strategy for TMM activation detection, which can categorise neuroblastomas into multiple clinical subgroups for risk stratification in routine histopathology practice.

Prominent Staining of MYCN Immunohistochemistry Predicts a Poor Prognosis in MYCN Non-Amplified Neuroblastoma

BACKGROUND

MYCN gene amplification is a powerful indicator of poor prognosis of neuroblastoma patients. However, MYCN non-amplified patients still showed heterogeneity in survival outcome. This study aimed to investigate the prognostic role of MYCN immunohistochemistry (IHC) in pre-treatment and post-treatment neuroblastoma tumors.

METHODS

215 untreated neuroblastoma tumors were stained with anti-MYCN antibody by immunohistochemical staining. 22 post-treatment tumors were used to compare MYCN staining with paired pre-treatment samples. Results were analyzed with other prognostic indicators.

RESULTS

Moderate or strong expression of MYCN was associated with unfavorable survival outcomes (P < .001). Prominent staining of MYCN IHC was 95% sensitive and 95% specific for the presence of MYCN gene amplification in this study. Ten of 214 (5%) patients showed prominent MYCN staining but MYCN non-amplification, and had a poor prognosis (29.6 ± 16.4%, 5-year overall survival). Most of cases (7/11, 64%) with high or moderate MYCN expression before chemotherapy showed lower expression in their tumors after chemotherapy.

CONCLUSION

MYCN protein overexpression was not only a sensitive and specific marker for MYCN gene amplification, but also a marker of poor prognosis in patients without MYCN amplification. However, MYCN protein expression was not always consistent before and after treatment.

Multifarious Functions of Butyrylcholinesterase in Neuroblastoma: Impact of BCHE Deletion on the Neuroblastoma Growth In Vitro and In Vivo

The physiological functions of butyrylcholinesterase (BChE) and its role in malignancy remain unexplained. Our studies in children newly diagnosed with neuroblastoma indicated that BChE expressions is proportional to MYCN amplification suggesting that pathogenesis of high-risk disease may be related to the persistent expression of abnormally high levels of tumor-associated BChE. BChE-deficient neuroblastoma cells (KO [knockout]) were produced from MYCN -amplified BE(2)-C cells (WT [wild-type]) by the CRISPR-Cas9 targeted disruption of the BCHE locus. KO cells have no detectable BChE activity. The compensatory acetylcholinesterase activity was not detected. The average population doubling time of KO cells is 47.0±2.4 hours, >2× longer than WT cells. Reduced proliferation rates of KO cells were accompanied by the loss of N-Myc protein and a significant deactivation of tyrosine kinase receptors associated with the aggressive neuroblastoma phenotype including Ros1, TrkB, and Ltk. Tumorigenicity of WT and KO cells in male mice was essentially identical. In contrast, KO xenografts in female mice were very small (0.37±0.10 g), ~3× smaller compared with WT xenografts (1.11±0.30 g). Unexpectedly, KO xenografts produced changes in plasma BChE similarly to WT tumors but lesser in magnitude. The disruption of BCHE locus in MYCN -amplified neuroblastoma cells decelerates proliferation and produces neuroblastoma cells that are less aggressive in female mice.

Combined Detection of Copy Number Variations of MYCN and ALK using Droplet Digital Polymerase Chain Reaction to Identify High-Risk Patients with Neuroblastoma

OBJECTIVE

The current study sought to explore the significance of copy number variations (CNVs) of MYCN (v-myc myelocytomatosis viral related oncogene, neuroblastoma derived [avian]) and ALK (anaplastic lymphoma kinase) genes individually as well as their combined impact on clinical outcome and overall survival of patients with neuroblastoma (NB).

METHODS

A total 71 individuals including healthy controls (n = 11), circulating DNA (n = 11), and primary tumors (n = 49) were evaluated to detect CNVs of MYCN and ALK genes using droplet digital polymerase chain reaction. Data were correlated with univariate and multivariate survival analysis.

RESULTS

CNVs of MYCN and ALK were detected in 27% and 18.2% from circulating DNA samples. A statistically significant difference in CNVs was noted between healthy controls and circulating DNA samples for MYCN (P = 0.001) and ALK (P = 0.004) genes. Further, we noted >70% concordance in CNVs of MYCN (P = 0.030) and ALK (P = 0.040) from primary tumors and concordant plasma samples of patients with NB. Multivariate survival analysis for disease-free survival (P = 0.031) and overall survival (P = 0.011) showed that CNVs of both genes emerged at step 1 and thus remained as significant markers for predicting early recurrence and shorter survival, respectively, for patients with NB.

CONCLUSIONS

Our study showed that the analysis of circulating DNA by droplet digital polymerase chain reaction is a helpful technique to identify high-risk patients for aggressive therapy at an early stage of disease. We also concluded that codetection of MYCN and ALK is a more powerful tool for identifying high-risk patients with NB. Thus, this study showed a novel coordinately significant prognostic role of MYCN and ALK CNVs.

Differential Impact of ALK Mutations in Neuroblastoma

PURPOSE

The tyrosine kinase receptor anaplastic lymphoma kinase (ALK) can be abnormally activated in neuroblastoma, and somatic ALK mutations occur in 6%-10% of patients. The differential clinical impact of these mutations has not been clearly elucidated.

METHODS

Data on patients with neuroblastoma harboring ALK mutations were retrospectively analyzed. ALK sequencing was performed by whole-genome sequencing, hybrid-based capture of targeted exomes, or hotspot ALK mutation profiling. The differential impact of ALK mutation site on clinical characteristics, response to treatment, and survival was analyzed. In a subgroup of patients with locoregional neuroblastoma diagnosed after 2014, the impact of all ALK mutations was compared with wild-type ALK.

RESULTS

Of 641 patients with neuroblastoma with ALK status analyzed on at least one tumor sample, 103 (16%) had tumors harboring ALK mutations. Mutations existed across all ages (birth to 67.8 years), stages (30% locoregional and 70% metastatic), and risk groups (20%, 11%, and 69% with low-, intermediate-, and high-risk disease, respectively). Mutation sites included F1174 (51%), R1275 (29%), R1245 (10%), and others (10%). Mutation site was not prognostic for progression-free survival or overall survival in the entire cohort, high-risk subgroup, or locoregional subgroup. Locoregional tumors with any ALK mutation were generally invasive: L2 by International Neuroblastoma Research Group staging in 30/31 patients with a 2-year progression-free survival (59%, 95% CI, 37.4 to 80.5) that was inferior to historical controls. This observation was corroborated in the post-2014 subgroup in which gross total resection was less likely for ALK-mutated tumors.

CONCLUSION

Somatic ALK mutations are present across all stages and risk groups of neuroblastoma. No specific mutation carries differential prognostic significance. Locoregional neuroblastoma has an invasive phenotype when harboring somatic ALK mutations in this population.

The challenge of defining "ultra-high-risk" neuroblastoma

Given the biological and clinical heterogeneity of neuroblastoma, risk stratification is vital to determining appropriate treatment. Historically, most patients with high-risk neuroblastoma (HR-NBL) have been treated uniformly without further stratification. Attempts have been made to identify factors that can be used to risk stratify these patients and to characterize an "ultra-high-risk" (UHR) subpopulation with particularly poor outcome. However, among published data, there is a lack of consensus in the definition of the UHR population and heterogeneity in the endpoints and statistical methods used. This review summarizes our current understanding of stratification of HR-NBL and discusses the complex issues in defining UHR neuroblastoma.

ALK in Neuroblastoma: Biological and Therapeutic Implications

Neuroblastoma (NB) is the most common and deadly solid tumour in children. Despite the development of new treatment options for high-risk NB, over half of patients relapse and five-year survival remains at 40-50%. Therefore, novel treatment strategies aimed at providing long-term disease remission are urgently sought. ALK, encoding the anaplastic lymphoma kinase receptor, is altered by gain-of-function point mutations in around 14% of high-risk NB and represents an ideal therapeutic target given its low or absent expression in healthy tissue postnatally. Small-molecule inhibitors of Anaplastic Lymphoma Kinase (ALK) approved in ALK fusion-positive lung cancer are currently undergoing clinical assessment in patients with ALK-mutant NB. Parallel pre-clinical studies are demonstrating the efficacy of ALK inhibitors against common ALK variants in NB; however, a complex picture of therapeutic resistance is emerging. It is anticipated that long-term use of these compounds will require combinatorial targeting of pathways downstream of ALK, functionally-related 'bypass' mechanisms and concomitant oncogenic pathways.