ICD-O M9473/3 eMedicine ped/2589 neuro/326 | DiseasesDB 31470 MeSH D018242 | |
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Primitive neuroectodermal tumor (PNET) is a malignant (cancerous) neural crest tumor. It is a rare tumor, usually occurring in children and young adults under 25 years of age. The overall 5 year survival rate is about 53%.
Contents
It gets its name because the majority of the cells in the tumor are derived from neuroectoderm, but have not developed and differentiated in the way a normal neuron would, and so the cells appear "primitive".
PNET belongs to the Ewing family of tumors.
Classification
It is classified into two types, based on location in the body: peripheral PNET and CNS PNET.
Peripheral PNET
The peripheral PNET (pPNET) is now thought to be virtually identical to Ewing sarcoma:
"Current evidence indicates that both Ewing's sarcoma and PNET have a similar neural phenotype and, because they share an identical chromosome translocation, they should be viewed as the same tumor, differing only in their degree of neural differentiation. Tumors that demonstrate neural differentiation by light microscopy, immunohistochemistry, or electron microscopy have been traditionally labeled PNETs, and those that are undifferentiated by these analyses have been diagnosed as Ewing's sarcoma."
PNET of the CNS
PNET of the CNS generally refer to supratentorial PNETs.
Model
Using gene transfer of SV40 large T-antigen in neuronal precursor cells of rats, a brain tumor model was established. The PNETs were histologically indistinguishable from the human counterparts and have been used to identify new genes involved in human brain tumor carcinogenesis. The model was used to confirm p53 as one of the genes involved in human medulloblastomas, but since only about 10% of the human tumors showed mutations in that gene, the model can be used to identify the other binding partners of SV40 Large T- antigen, other than p53.