Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Somatostatin receptors are expressed on certain neural crest-derived tumors, including pancreatic islet cell and carcinoid tumors, medullary thyroid carcinomas, pheochromocytomas, and paragangliomas. The authors evaluated the expression of high affinity somatostatin receptors in childhood neuroblastoma using autoradiography techniques with the somatostatin analogue 125I-octreotide or 125I-[Leu8,D-Trp22,Tyr25]-SS-28 as the radioligand. Thirty tumors from 30 children with neuroblastoma were analyzed. Twenty-three of 30 tumors that were tested expressed somatostatin receptors. Correlation of somatostatin receptor expression with survival was statistically significant. The survival of those patients whose tumors expressed somatostatin receptors was of longer duration than that of patients whose tumors did not. This was an independent prognostic factor. Somatostatin receptors were expressed more frequently in tumor tissue from patients with lower stages of disease and in those with no evidence of N-myc amplification. Tumoral somatostatin receptors are expressed in a subgroup of patients with childhood neuroblastoma. Survival analysis in this group of patients indicates that somatostatin receptor expression is a favorable prognostic factor. This finding may have important implications for the therapy of children with this malignancy.
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PMID:Expression of somatostatin receptors in childhood neuroblastoma. 780 87

Neuroblastoma is the most common extracranial solid tumor of children. Neuroblastoma tumors derive from the neural crest and synthesize neurotransmitters including the neuropeptide somatostatin. This study was designed to characterize somatostatin receptors both in primary neuroblastoma tumors and in two neuroblastoma cell lines, SKNSH and IMR32. Somatostatin receptors were identified in 6 of 7 Stage I and II compared to 7 of 19 Stage III and IV tumors. Down-regulation of somatostatin receptor binding was observed in five tumors during disease progression. A lack of high affinity binding of somatostatin was identified as a poor prognostic indicator; negative binding correlated with advanced disease and death. Somatostatin receptor binding was observed in the IMR32 cell line, but not in the SKNSH cell line. IMR32 cells demonstrated a single class of high affinity binding sites for both somatostatin and a synthetic analogue, octreotide (Kd 0.16 +/- 0.05 nM and 0.89 +/- 0.23 nM, respectively). Somatostatin and octreotide inhibited both vasoactive intestinal peptide-mediated and forskolin-mediated cyclic AMP accumulation in IMR32 cells. Somatostatin and octreotide inhibition of signal transduction was attenuated by pretreatment of the cells with pertussis toxin. Octreotide inhibited proliferation of IMR32 cells by 70% in a 6-day culture. In contrast, octreotide did not exhibit high affinity binding in SKNSH cells and had no effect on cyclic AMP accumulation or on proliferation in SKNSH cells. Together, these data indicate that octreotide interacts with high affinity somatostatin receptors to modulate signal transduction and regulate proliferation in neuroblastoma cell lines. These data also suggest that somatostatin receptor expression may be an independent prognostic factor in primary neuroblastoma tumors.
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PMID:Characterization of somatostatin receptors on human neuroblastoma tumors. 812 88

Tumor cell expression of specific high-affinity somatostatin receptors has been associated with a favorable prognosis in children with neuroblastoma. The purpose of this study was (1) to document intraoperatively the in vivo binding of the somatostatin analogue 125I-tyr3-octreotide to high-affinity somatostatin receptors expressed on human neuroblastoma, using a hand-held gamma detector; (2) to determine whether gamma-probe detection of radioligand binding to tumor receptors could identify occult malignancy; and (3) to determine the safety and biodistribution of 125I-tyr3-octreotide in children. Six children with stage III or IV neuroblastoma received an intravenous injection of 125I-tyr3-octreotide and underwent operative exploration using gamma-probe detection of radioligand binding to tumor somatostatin receptors. Tissue that demonstrated in vivo binding of 125I-tyr3-octreotide, or that was suspicious for tumor, was extirpated and analyzed by histopathology, immunohistochemistry, and microautoradiography. The biodistribution of 125I-tyr3-octreotide was recorded intraoperatively over time. Tumor tissue from each child also was assayed in vitro for somatostatin receptor expression by competitive binding studies using 125I-tyr3-octreotide. In vivo binding of 125I-tyr3-octreotide to malignant tissue was documented in the five children with a known tumor burden. Seventeen sites of radioreceptor binding were amenable to resection. Histopathological analysis confirmed neuroblastoma in 15 of these specimens. Four of the 15 proven tumor foci were occult malignancies. Every site of histologically proven neuroblastoma demonstrated in vivo binding of 125I-tyr3-octreotide. Five of seven sites histologically negative for neuroblastoma also were negative for in vivo radioreceptor binding. Microautoradiography confirmed in vivo binding of 125I-tyr3-octreotide to tumor cells. Uptake of 125I-tyr3-octreotide in abdominal organs occurred within 15 minutes of injection, was highest in the liver and gallbladder, and decreased over 24 hours. The conclusions were as follows. (1) 125I-tyr3-octreotide binds, in vivo, to somatostatin receptors on neuroblastoma, with 100% sensitivity and 71% specificity. (2) Occult neuroblastoma is found through gamma-probe detection of radioligand binding to receptors. (2) The biodistribution of 125I-tyr3-octreotide reflects the hepatobiliary clearance of this radionuclide. (4) Radioreceptor-guided surgery may safely provide more complete operative staging and cytoreduction of neuroblastoma.
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PMID:Intraoperative detection and resection of occult neuroblastoma: a technique exploiting somatostatin receptor expression. 858 29

Paediatric oncology continues to search for improved methods for the early detection and effective treatment of solid tumours, especially those of the nervous system, which constitute 50% of all solid tumours in children and adolescents. These tumours, including neuroblastoma, meningioma, low-grade astrocytoma and medulloblastoma express somatostatin receptors and can be imaged effectively using 111In-octreotide. In addition to improved imaging techniques, somatostatin analogues are being developed for use in radioreceptor-guided surgery, as a component of adjuvant chemotherapy and for supportive treatment. Radioreceptor-guided surgery utilises 125I-Tyr3-octreotide or 125I-lanreotide to detect tumour foci within minutes of injection. It allows the detection of 0.1-1.0 mg tumour (1 x 10(5) to 1 x 10(6) tumour cells). This technique has successfully located foci of occult tumour in children with neuroblastoma. Somatostatin analogues are also currently being studied as tumour growth inhibitors between regular chemotherapy cycles and for the treatment of chemotherapy-induced pancreatitis in children with leukaemia. Research on somatostatin receptor subtype expression in paediatric tumours suggests that further investigation of analogue effects on growth inhibition and induction of differentiation will contribute to improved therapy for children with solid tumours.
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PMID:Clinical use of somatostatin analogues in paediatric oncology. 881 66

The international workshop on metaiodobenzylguanidine (MIBG) and radiolabeled somatostatin analogs held in Rome in June, 1994 addressed a wide range of topics which might be classified into five broad general themes: Theme 1. The role of MIBG for the location of neuroendocrine tumors. A) The range of tumors in which MIBG scintigraphy is effective (pheochromocytomas, neuroblastoma, chemodectoma and other APUDomas). B) The increasing popularity of 123I as a radiolabel for MIBG (potential advantages in planar and SPECT imaging). C) MIBG as the prototype of a family of radiopharmaceuticals exploiting the biogenic amine uptake and storage mechanisms. (Other radiohalides 124I, 125I, 87Br, 211At, 18F; other PET radiopharmaceuticals such as 11C-epinephrine, 11C-hydroxyephedrine). Theme 2. The role of MIBG as an in vivo scintigraphic probe of the sympathetic nervous system. A) Cardiac sympathetic innervation (in cardiomyopathy, myocardial infarction, and as a prognostic index for cardiac transplantation). B) Pulmonary MIBG uptake as index of pulmonary endothelial/sympathetic function (MIBG by both the intravenous and inhaled routes of administration). Theme 3. MIBG for the radiopharmaceutical therapy of neuroendocrine tumors. A) Treatment of neuroblastoma early in the natural history of the disease (MIBG therapy as initial management, MIBG therapy combined with other modalities--e.g., chemotherapy and bone marrow transplantation). Theme 4. The role of radiolabeled somatostatin analogs for the location of neuroendocrine and other tumors. A) The range of tumors in which somatostatin receptor radiopharmaceutical scintigraphy is effective (pituitary tumors, central nervous system tumors, carcinoids, islet cell tumors, medullary thyroid carcinoma, small cell lung cancer, APUDomas). B) The superiority of 111In over 123I as a radiolabel (the future of potential 99mTc and other labels). C) Somatostatin receptor scintigraphy in autoimmune and other disorders. D) Pentetreotide as the prototype of a wide range of radiolabeled peptides as radiopharmaceuticals for the in vivo depiction of the receptors for peptide hormones, lymphokines, paracrine and other information transmitting molecules (the general concepts include the use of long-acting, slowly degraded analogs and the development of generally applicable labeling techniques. Examples include 123I-ANF, labeled interleukins and other lymphokines). Theme 5. Comparisons of MIBG and pentetreotide scintigraphy for the location of neuroendocrine tumors. A) The range of neuroendocrine and other tumors (e.g., pheochromocytomas, neuroblastomas, carcinoids, islet cell tumors and other APUDomas).
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PMID:Ten years of experience with MIBG applications and the potential of new radiolabeled peptides: a personal overview and concluding remarks. 900 76

Five distinct human somatostatin receptor subtypes have recently been cloned and characterized. Previous studies have suggested that these receptor subtypes might display coexistent localization, based on in situ hybridization or immunoblockage experiments. Here we provide evidence for coexistence of somatostatin receptor subtypes 2 and 5 in the human neuroblastoma cell line LA-N-2, using a combined approach with RT-PCR and receptor binding studies with somatostatin analogues. Somatostatin receptor subtypes simultaneously localized to a single cell might serve distinct functions in terms of targeting to different intraneuronal compartments or subtype specificity against so far unidentified somatostatin-related peptides.
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PMID:Coexistence of somatostatin receptor subtypes in the human neuroblastoma cell line LA-N-2. 900 11

Neural-crest tumours, including neuroblastomas, express somatostatin receptors. This can be shown by radionuclide labelling of octreotide, a somatostatin analogue. Studies on imaging with this substance have dealt with childhood neuroblastomas. Olfactory neuroblastoma (aesthesioneuroblastoma) is a rare tumour in which somatostatin receptor content has not been analysed, nor have radionuclide methods for diagnostic purposes been described. We report a case of olfactory neuroblastoma, in which scanning with 111In-labelled octreotide was performed. A strong uptake was seen at the base of the skull. This was confirmed as a recurrent tumour by magnetic resonance (MR) imaging. Uptake was also observed in the neck and chest, indicating extensive spread of the disease. Somatostatin receptor expression has been shown to correlate with prognosis in childhood neuroblastoma. The accuracy of labelled octreotide in the diagnosis of olfactory neuroblastoma indicates that it might be useful in radionuclide therapy of patients with advanced disease, when no other treatment modalities are available.
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PMID:Somatostatin receptor imaging of olfactory neuroblastoma. 901 33

Three radiolabelled substances, 111In-pentetreotide, 99mTc-(V)DMSA and 123I-MIBG with different kinetics but similar tumor seeking behavior, were i.v. injected to assess and correlate their clinical value in metastatic malignant pheochromocytomas (4 patients), stage III and IV neuroblastomas (7 patients) and medullary thyroid carcinomas (6 patients). All II pheochromocytoma/neuroblastoma patients received i.v. a dose of III MBq (3 mCi) of 123I-MIBG and 185 MBq (5 mCi) of 111In-pentetreotide, within approximately weeks each other. Furthermore, in 4 of these patients as well as in all medullary thyroid carcinoma patients 111 MBq (3 mCi) of 99mTc-(V)DMSA were applied i.v. I week prior to the pentetreotide/mlBG scans. Four patients (malignant pheochromocytoma) with a total of 7 foci showing MIBG accumulation had 3 sites with pentetreotide and 1 site with (V)DMSA uptake, while in 7 patients (neuroblastora) with 15 foci showing MIBG accumulation 10 sites had detectable pentetreotide and 3 sites detectable (V)DMSA. Of the three radiotracers, 111In-pentetreotide used for somatostatin receptor identification holds promise mainly in cases where foci imaged with 123I-MIBG are negative. 111In-pentetreotide is unlikely to replace 123I-MIBG as a first-line routine diagnostic scintigraphic modality; compared to pentetreotide or MIBG, (V)DMSA seems to be highly sensitive only in medullary thyroid carcinomas.
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PMID:Comparison of In-111 pentetreotide, Tc-99m (V)DMSA and I-123 mlBG scintimaging in neural crest tumors. 917 99

Neuroblastoma, a childhood tumour of the sympathetic nervous system, may in some cases differentiate to a benign ganglioneuroma or regress due to apoptosis. Somatostatin may inhibit neuroblastoma growth and induce apoptosis in vitro and was therefore investigated. Using a radioimmunoassay, we found that all ganglioneuromas contained high somatostatin concentrations (> 16 pmol/g), significantly higher than neuroblastomas (n = 117, median 2.8 pmol/g), healthy adrenals, Wilms' tumours, phaeochromocytomas and other neuroendocrine tumours (P < 0.001). Neuroblastomas contained more somatostatin than control tumours (P < 0.001-0.05). Neuroblastomas amplified for the MYCN oncogene contained less somatostatin than non-amplified tumours (1.2 pmol/g versus 4.0 pmol/g, respectively; P = 0.026). In a clinically unfavourable neuroblastoma subset (age > 12 months, stage 3 or 4) 16 children with high concentrations of somatostatin in primary tumours had a better prognosis than 23 with low somatostatin (46.7% versus 0% survival at 5 years, P < 0.005). Scintigraphy using 111In-pentetreotide identified tumours expressing high-affinity somatostatin receptors in vivo. However, no significant correlation was found between somatostatin receptor expression and peptide content in 15 tumours. Similarly, human SH-SY5Y neuroblastoma xenografts grown in nude rats showed low somatostatin concentrations, but were positive for somatostatin receptor scintigraphy. Treatment of these rats with the somatostatin analogue octreotide seemed to upregulate in vivo receptor expression of somatostatin and vasoactive intestinal peptide more effectively than 13-cis retinoic acid. In conclusion, somatostatin in neuroblastoma is associated with differentiation to benign ganglioneuromas in vivo and favourable outcome in advanced tumours. Furthermore, somatostatin receptor scintigraphy may identify tumours with high-affinity receptors in children that might benefit from targeted therapy using synthetic somatostatin analogues.
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PMID:Somatostatin in neuroblastoma and ganglioneuroma. 951 58

We previously reported the presence of somatostatin (SS-14)-binding sites in a wide panel of human neuroblastoma (NB) tumor cell lines. Given that the adrenal gland and its relative embryonal and adult tumors express an abundance of mRNA for somatostatin receptor type 2 (sst2) mRNA, we studied the quantitative expression of sst2 in 6 NB cell lines and 15 primary tumors using competitive reverse transcription (RT)-PCR. This method uses an insertion mutant of the target gene as a competitor for the RT-PCR reaction, thus allowing exact quantitation of sst2 mRNA abundance. We found expression of specific transcripts for sst2 in all of the NB cell lines and tumors investigated (range, 9 x 10(5)-4 x 10(9) molecules/microg RNA). In NB cells, the expression of sst2 was highly correlated with SS-14-binding sites (R = 0.93). In primary tumors, sst2 was positively related to the expression of the neuroendocrine marker secretogranin II (P < 0.05) and negatively related to N-myc amplification (a poor prognostic factor, P < 0.005) and metastatic dissemination (P < 0.05). In addition, Kaplan-Meier curves indicate that sst2 expression is positively related to survival (P = 0.01). In a patient with stage IVs disease (a spontaneously regressing form), we found the highest sst2 expression (4 x 10(9) molecules/microgram RNA), a value relatively similar to that of normal adrenal. In conclusion, these data indicate that quantitation of sst2, as assessed with competitive RT-PCR, could represent a new prognostic tool in the neuroendocrine tumor NB. Since sst2 recognizes octreotide with high affinity, these findings could also have both diagnostic and therapeutic value.
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PMID:Quantitation of somatostatin receptor type 2 gene expression in neuroblastoma cell lines and primary tumors using competitive reverse transcription-polymerase chain reaction. 981 27


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