AbstractsBiology & Animal Science

Neuroblastomas, the most coilllllon extracranial solid tumor found in children with a mean diagnosis age of 18 months, arise from malignant transformation of undifferentiated neuronal stem cells. These tumors often derive in the sympathetic nervous system. It has been suggested that tumors typically manifested in this area are more likely caused by spontaneous or predisposed genetic factors, rather than environmental exposure. However, most neuroblastoma cases are a result of spontaneous genetic changes such as chromosomal ploidy, activation of known oncogenes and tumorcell ploidy changes in somatic cells. Understanding the molecular bases that underlie these clinical outcomes may provide further insight into the disease pathogenesis. The abnormal expressiqn of a numoer of genes has already been linked to specific clinical diagnoses suggestfu.g that variance of specific genes may be causal in neuroblastoma mortality rates. One such gene, neuroblastorua-derived myelocytomatosis oncogene (MYCN), has been shown to positively correlat~ with poor neqroplastoma prognosis. MYCN is a transcription factor that forms heterodimers with transcriptiqnal co-factors, through helix loop helix lel.Jcine interactions, to target genes and affect downstream transcriptional activity. MYCN has been shown to regulate gene express~on as both an activator as well as a repressor in genes involved in fun