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Neuroblastomas are tumors of the neural crest
derivatives in the adrenal medulla and autonomic nervous system. The
incidences of neuroblastomas are higher in children than in adults.
However, neuroblastomas are often microscopic in infants and small children,
and many regress before they can be clinically diagnosed. When neuroblastomas
do not regress, they can become malignant ganglioneuromas, ganglioneuroblastomas,
or pheochromocytomas. Neuroblastomas often consist of cells morphologically identical to
migrating neural crest cells - mesenchymal
cells that simply fail to differentiate. The tumors are often composed
of several neural crest derived tissues within a single tumor: melanocytes,
neurons, Schwann cells, and chondroblasts. (Hall,
157) These tumor cells are neoplastic cells - they are neither embryonic
cells nor normal, differentiated adult cells. Diagnosis and detection
of these neoplastic neuroblastomas can be confirmed by abnormally high
production of catecholamines - which can be detected by the measurement
of urinary vinillinemndelic acid, a catecholamine metabolite. More recent
research on neuroblastomas has been rewarding. Mice neuroblastomas have
been maintained in vivo and in vitro as a tumor cell line; these tumor
cells respond to lectins - a tumor promoting agent that has been observed
to induce increased neural crest proliferation - via lectin receptors.
Thus, neural crest cell division can be manipulated in the lab. (Hall,
159) |
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