7345

UCHL1

PARK5|PGP 9.5|PGP9.5|PGP95|Uch-L1;ubiquitin carboxyl-terminal esterase L1 (ubiquitin thiolesterase);UCHL1;ubiquitin carboxyl-terminal esterase L1 (ubiquitin thiolesterase)

neuron cytoplasmic protein 9.5|ubiquitin C-terminal hydrolase|ubiquitin carboxyl-terminal hydrolase isozyme L1|ubiquitin thioesterase L1

4p14

protein-coding

Small round cell tumors of childhood can be histologically ambiguous, can require tumor markers for an accurate diagnosis, and include neuroblastoma, peripheral primitive neuroectodermal tumor (pPNET), Ewing's sarcoma (ES), lymphoma, and rhabdomyosarcoma. Because the cell type of origin for ES remains controversial, characterizing gene expression in ES can provide diagnostic markers and lead to better understanding of tumor biology. We studied RNA expression of the neuronalgenes protein gene product 9.5 (PGP 9.5) and tyrosine hydroxylase (TH) by Northern analysis in cell lines and tissue from small round cell tumors. PGP 9.5showed strong expression in 17 of 17 neuroblastoma cell lines, 9 of 9 pPNET celllines, and 11 of 11 ES cell lines. PGP 9.5 was weakly expressed in 1 of 1 alveolar rhabdomyosarcoma cell lines but not in 1 of 1 embryonal rhabdomyosarcomas, and weak expression was seen in 1 of 7 leukemia cell lines. In tumor tissue, ALL 12 neuroblastomas expressed PGP 9.5, as did ALL 7 pPNET and ALL 7 ES. PGP 9.5 was very weakly expressed in 6 of 9 rhabdomyosarcomas and 1 of 9 lymphomas. TH was expressed only in neuroblastomas, and no TH expression was seen in cell lines or tissue from other tumors. As high expression of PGP 9.5 was only found in neural tumors; PGP 9.5 expression by ES provides further evidence for aneural origin of this tumor, whereas TH expression is highly specific for neuroblastomas. PGP 9.5 expression should allow sensitive detection of minimal residual disease for ES and pPNET using reverse transcription-PCR, and the variability in TH and PGP 9.5 expression levels in neuroblastomas indicates thatexpression of both genes should be used for monitoring minimal residual disease by reverse transcription-PCR.

OBJECTIVE: To determine whether circulating tumor cells are present in patients with localized or disseminated neuroblastoma (NB). METHODS: Sixteen pediatric malignant tumor cell lines, including 10 NB, 4 primitive neuroectodermal tumor (PENT), 2 Wilms' tumor and 39 samples (tumor tissue, bone marrow and peripheral blood) from 8 patients with NB, were evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR) using two markers: neuroendocrine protein gene products 9.5 (PGP 9.5) and tyrosine hydroxylase (TH). RESULTS: Analysis of RT-PCR products by agarose electrophoresis demonstrated that in culture cell lines the specificity for NB was highest in TH (9/10 with NB, 3/4 with PNET, 0/2 with Wilms' tumor) and the sensitivity was highest in PGP 9.5 10(-7). PGP 9.5 and TH mRNA were undetectable in the peripheral blood mononuclear cells (PBMNC) from normal children. expression of these markers in 8 patients with NB at diagnosis and during treatment was found positive in 5 out of 8, ALL had been proved paralleling with their disease status. Two of the 5 became negative after further treatment. CONCLUSIONS: These systems allow the detectionof circulating NB cells with higher sensitivity and specificity. When RT-PCR is clinically used for the detection of NB cells in blood, that both PGP 9.5 and THshould be selected is recommended. The assessment of bone marrow alone might notbe used as a single index of tumor dissemination.