Tumor formation Gene amplification

Some neuroblastoma cells overexpress the c-Kit receptor for its ligand, stem cell factor (SCF), and release SCF in an autocrine loop for self-stimulation of mitoses. Imatinib mesylate suppresses PDGF and tyrosine kinase c-Kit (GDI 17) expression. Somatostatin inhibited PDGF-induced phosphorylation of PDGFR and inhibited ras gene amplification. For local invasion, these tumor cells release MMP2/9. The synthetic MMP inhibitor, prinomastat, suppresses MMP production and tumor cell locomotion. However, MMP expression is promotional for neuroblastoma cell differentiation. The presence of MMP is necessary for the neurite formation of retinoic acid-treated neuroblastoma cells neurite formation is the first sign of differentiation induction (vide infra) [1624]. 

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