**Chapter 7 99**

Targeting MYC and HDAC8 with a Combination of siRNAs Inhibits Neuroblastoma Cells Proliferation In Vitro and In Vivo Xenograft Tumor Growth *by Nagindra Prashad*

Preface

Well-differentiated cellular elements, tissues, and organs can originate from the cells of the neural crest. The multipotent differentiation potential of these cell lines is well known, and therefore it is not surprising that the tumors derived from them represent a group of heterogeneous neoplasms. These neoplasms can arise in localizations of the body where cells derived from the neural crest are normally present; however, they can also occur in unusual tissues and locations and in this case, the explanation could be associated with the presence of stem cells that have been shown to be present also in tissues not originating from the neural crest. The classification of tumors derived from neural crest cells has undergone various changes over time. Previously some tumors had been declared of neural crest origin, such as neuroendocrine tumors of the gastrointestinal tract, but a different embryological origin was subsequently demonstrated. Primitive neuroectodermal tumors have always been considered to originate from the cells of the neural crest, but their origin is still unknown today. Pheochromocytoma, paraganglioma and neuroblastoma are the most common neural crest-derived tumors in adults and children, respectively. These neoplasms are associated with significant morbidity and mortality. Although these tumors have different clinical manifestations, courses, and prognoses, their origin can be considered common. Various genetic studies are underway to identify their similarities and differences. Currently being investigated is the role of Stathmin 1 signaling in the pathogenetic mechanism of neuroblastoma and pheochromocytoma, such as the relevance of the PHOX2B gene. Protein is still being studied in the pathogenesis of pheochromocytoma, despite having a fundamental role in the development of precursor cells derived from the neural crest. In this book, we review the current concept of neural crest-cells derived tumors, focusing on pheochromocytoma/paraganglioma and neuroblastoma. In conclusion, I would like to thank everyone who has helped

and supported us in this ambitious, long, and demanding job.

**Pasquale Cianci** University of Foggia,

**Enrico Restini**

**Amit Agrawal**

"Lorenzo Bonomo" Hospital,

All India Institute of Medical Sciences,

ASL BAT, Andria, Italy

ASL BAT, Andria, Italy

India

Department of Surgery and Traumatology,
