Genome instability model of metastatic neuroblastoma tumorigenesis by a dictionary learning algorithm

Prediction of Composite Clinical Outcomes for Childhood Neuroblastoma Using Multi-Omics Data and Machine Learning

Neuroblastoma is a common malignant tumor in childhood that seriously endangers the health and lives of children, making it essential to find effective prognostic markers to accurately predict their clinical outcomes. The development of high-throughput technology in the biomedical field has made it possible to obtain multi-omics data, whose integration can compensate for missing or unreliable information in a single data source. In this study, we integrated clinical data and two omics data, i.e., gene expression and DNA methylation data, to study the prognosis of neuroblastoma. Since the features in omics data are redundant, it is crucial to conduct feature selection on them. We proposed a two-step feature selection (TSFS) method to quickly and accurately select the optimal features, where the first step aims at selecting candidate features and the second step is to remove redundant features among them using our proposed maximal association coefficient (MAC). Our goal is to predict composite clinical outcomes for neuroblastoma patients, i.e., their survival time and vital status at the last follow-up, which was validated to be two inter-correlated tasks. We conducted a series of experiments and evaluated the experimental results using accuracy and AUC (area under the ROC curve) evaluation metrics, which indicated that by the combination of the integration of the three types of data, our proposed TSFS method and a multi-task learning method can synergistically improve the reliability and accuracy of the prediction models.

17q Gain in Neuroblastoma: A Review of Clinical and Biological Implications

Neuroblastoma (NB) is the most frequent extracranial solid childhood tumor. Despite advances in the understanding and treatment of this disease, the prognosis in cases of high-risk NB is still poor. 17q gain has been shown to be the most frequent genomic alteration in NB. However, the significance of this remains unclear because of its high frequency and association with other genetic modifications, particularly segmental chromosomal aberrations, 1p and 11q deletions, and MYCN amplification, all of which are also associated with a poor clinical prognosis. This work reviewed the evidence on the clinical and biological significance of 17q gain. It strongly supports the significance of 17q gain in the development of NB and its importance as a clinically relevant marker. However, it is crucial to distinguish between whole and partial chromosome 17q gains. The most important breakpoints appear to be at 17q12 and 17q21. The former distinguishes between whole and partial chromosome 17q gain; the latter is a site of IGF2BP1 and NME1 genes that appear to be the main oncogenes responsible for the functional effects of 17q gain.

An overview of neuroblastoma cell lineage phenotypes and in vitro models

This review was conducted to present the main neuroblastoma (NB) clinical characteristics and the most common genetic alterations present in these pediatric tumors, highlighting their impact in tumor cell aggressiveness behavior, including metastatic development and treatment resistance, and patients' prognosis. The distinct three NB cell lineage phenotypes, S-type, N-type, and I-type, which are characterized by unique cell surface markers and gene expression patterns, are also reviewed. Finally, an overview of the most used NB cell lines currently available for in vitro studies and their unique cellular and molecular characteristics, which should be taken into account for the selection of the most appropriate model for NB pre-clinical studies, is presented. These valuable models can be complemented by the generation of NB reprogrammed tumor cells or organoids, derived directly from patients' tumor specimens, in the direction toward personalized medicine.

Telomere Maintenance in Pediatric Cancer

Telomere length has been proposed as a biomarker of biological age and a risk factor for age-related diseases and cancer. Substantial progress has been made in recent decades in understanding the complex molecular relationships in this research field. However, the majority of telomere studies have been conducted in adults. The data on telomere dynamics in pediatric cancers is limited, and interpretation can be challenging, especially in cases where results are contrasting to those in adult entities. This review describes recent advances in the molecular characterization of structure and function of telomeres, regulation of telomerase activity in cancer pathogenesis in general, and highlights the key advances that have expanded our views on telomere biology in pediatric cancer, with special emphasis on the central role of telomere maintenance in neuroblastoma. Furthermore, open questions in the field of telomere maintenance research are discussed in the context of recently published literature.

Neuroblastoma by chance

Neuroblastoma is a pediatric cancer of embryonic origin from neural crest cells. Neuroblastoma has a great medical and social impact because it is occurring with major frequency in pre-scholar age with metastatic disease showing less than 40% of survival at 5-years. In children, metastatic neuroblastoma has very few recurrent mutations but several chromosome structural copy variations. The tumorigenesis of neuroblastoma is still largely unknown; however recently, genomic wide association studies have shown that several gene allelic variants are associated with neuroblastoma predisposition. Many of these gene variants are related to maintaining the chromatin and mitosis integrity. In the present report, I suggest that neuroblastoma predisposing alleles may match by chance influencing the chromatin structure already during the early phases of embryonic life and inducing chromosome instability and structural damages.

Chromosome instability in neuroblastoma

Neuroblastoma is a neural crest-derived tumor that accounts for 7-10% of all malignancies in children and ~15% of all childhood cancer-associated mortalities. Approximately 50% of patients are characterized as high-risk (HR) and have an overall survival of <40% at 5 years from diagnosis. HR patients with unfavorable prognosis exhibit several structural copy number variations (CNVs), whereas localized tumors belonging to patients in the low- and intermediate-risk classes, have favorable outcomes and display several numerical CNVs. Taken together these results are indicative of chromosome instability (CIN) in neuroblastoma tumor cells. The present review discusses multiple aspects of CIN including methods of measuring CIN, CIN targeting as a therapeutic strategy in cancer and the effects of CIN in neuroblastoma development and aggressiveness with particular emphasis on the CIN gene signature associated with HR neuroblastoma patients.

Loss of DNA Damage Response in Neuroblastoma and Utility of a PARP Inhibitor

Background

Neuroblastoma (NB) is the most common solid tumor found in children, and deletions within the 11q region are observed in 11% to 48% of these tumors. Notably, such tumors are associated with poor prognosis; however, little is known regarding the molecular targets located in 11q.

Methods

Genomic alterations of ATM , DNA damage response (DDR)-associated genes located in 11q ( MRE11A, H2AFX , and CHEK1 ), and BRCA1, BARD1, CHEK2, MDM2 , and TP53 were investigated in 45 NB-derived cell lines and 237 fresh tumor samples. PARP (poly [ADP-ribose] polymerase) inhibitor sensitivity of NB was investigated in in vitro and invivo xenograft models. All statistical tests were two-sided.

Results

Among 237 fresh tumor samples, ATM, MRE11A, H2AFX , and/or CHEK1 loss or imbalance in 11q was detected in 20.7% of NBs, 89.8% of which were stage III or IV. An additional 7.2% contained ATM rare single nucleotide variants (SNVs). Rare SNVs in DDR-associated genes other than ATM were detected in 26.4% and were mutually exclusive. Overall, samples with SNVs and/or copy number alterations in these genes accounted for 48.4%. ATM-defective cells are known to exhibit dysfunctions in homologous recombination repair, suggesting a potential for synthetic lethality by PARP inhibition. Indeed, 83.3% NB-derived cell lines exhibited sensitivity to PARP inhibition. In addition, NB growth was markedly attenuated in the xenograft group receiving PARP inhibitors (sham-treated vs olaprib-treated group; mean [SD] tumor volume of sham-treated vs olaprib-treated groups = 7377 [1451] m 3 vs 298 [312] m 3 , P = .001, n = 4).

Conclusions

Genomic alterations of DDR-associated genes including ATM, which regulates homologous recombination repair, were observed in almost half of NBs, suggesting that synthetic lethality could be induced by treatment with a PARP inhibitor. Indeed, DDR-defective NB cell lines were sensitive to PARP inhibitors. Thus, PARP inhibitors represent candidate NB therapeutics.

11q deletion in neuroblastoma: a review of biological and clinical implications

Deletion of the long arm of chromosome 11 (11q deletion) is one of the most frequent events that occur during the development of aggressive neuroblastoma. Clinically, 11q deletion is associated with higher disease stage and decreased survival probability. During the last 25 years, extensive efforts have been invested to identify the precise frequency of 11q aberrations in neuroblastoma, the recurrently involved genes, and to understand the molecular mechanisms of 11q deletion, but definitive answers are still unclear. In this review, it is our intent to compile and review the evidence acquired to date on 11q deletion in neuroblastoma.

Growth, progression and chromosome instability of Neuroblastoma: a new scenario of tumorigenesis?

BACKGROUND

Neuroblastoma is a pediatric cancer with a low survival rate of patients with metastatic stage 4 disease. Tumor aggressiveness and progression have been associated with structural copy number variations (CNVs) that are observed in malignant cells. In contrast, localized Neuroblastomas, which are associated with a low number of structural CNVs but frequent numerical CNVs, are less aggressive, and patients have good outcomes. Finally, whole-genome and whole-exome sequencing of Neuroblastoma tissues have shown few damaging mutations in these tumors.

CONCLUSIONS

In the present report it is proposed that chromosome instability (CIN) plays a major role in Neuroblastoma tumorigenesis and that CIN is already present in the early phases of tumor development. High CIN can promote several types of chromosomal damage including chromothripsis, gene deletion, amplification and rearrangements, which deregulate gene expression. Indeed, gene rearrangements have been reported as a new scenario in the development of Neuroblastoma, which supports the hypothesis that CIN is an early step preliminary to the late catastrophic events leading to tumor development.