Diagnostic utility of cyclin D1 in the diagnosis of small round blue cell tumors in children and adolescents.

Small round blue cell tumors (SRBCTs) of children and adolescents are often diagnostically challenging lesions. With the increasing diagnostic approach based on small biopsies, there is the need of specific immunomarkers that can help in the differential diagnosis among the different tumor histotypes to assure the patient a correct diagnosis for proper treatment. Based on our recent studies showing cyclin D1 overexpression in both Ewing sarcoma/primitive peripheral neuroectodermal tumor (EWS/pPNET) and peripheral neuroblastic tumors (neuroblastoma and ganglioneuroblastoma), we immunohistochemically assessed cyclin D1 immunoreactivity in 128 cases of SRBCTs in children and adolescents to establish its potential utility in the differential diagnosis. All cases of EWS/pPNET and the undifferentiated/poorly differentiated neuroblastomatous component of all peripheral neuroblastic tumors exhibited strong and diffuse nuclear staining (>50% of neoplastic cells) for cyclin D1. In contrast, this marker was absent from rhabdomyosarcoma (regardless of subtype) and lymphoblastic lymphoma (either B- or T-cell precursors), whereas it was only focally detected (<5% of neoplastic cells) in some cases of Wilms tumor (blastemal component) and desmoplastic small round cell tumor. Our findings suggest that cyclin D1 can be exploitable as a diagnostic adjunct to conventional markers in confirming the diagnosis of EWS/pPNET or neuroblastoma/ganglioneuroblastoma. Its use in routine practice may also be helpful for those cases of SRBCT with undifferentiated morphology that are difficult to diagnose after application of the conventional markers.

Crinophagy in neuroblastoma: a case report and review of the literature.

Crinophagy is a well-described ultraphysiological phenomenon encountered in a variety of cells and tissues. This process reflects a form of autophagy in which degradation of excess or nonfunctional cellular constituents occurs, specifically of neuroendocrine granules. The diagnostic ultrastructural features are the identification of neuroendocrine granules within lysosomes, often encased in or accompanied by myelin bodies. An impressive variety of neuroendocrine/secretory cells and tumors have demonstrated crinophagy from the neuroendocrine cells of the pancreas, small bowel, prostate, and urinary tract. To our knowledge, however, crinophagy has not been previously described in neuroblastoma, despite the fact that these tumors characteristically produce neuroendocrine granules in abundance. This case further supports the idea that crinophagy represents a common ultrastructural mechanism for the disposal and degradation of excess neuroendocrine granules.

Expression of endothelin system in neuroblastic tumors: close association of endothelin-1 and endothelin B receptor expression with differentiation of tumor cells.

Although a critical role of the endothelin (ET) system in differentiation of neural crest cells has been reported, implication of the ET system in human neuroblastic tumors has not been fully elucidated. We immunohistochemically examined for localization of ET-1, ET-3, ET-A receptor (ET-A), and ET-B receptor (ET-B) in 24 ganglioneuromas, 8 ganglioneuroblastomas, 37 neuroblastomas, 14 normal sympathetic ganglia, and 10 fetal adrenal glands with regard to neuroblastic cell differentiation. Neuroblasts in fetal adrenal glands expressed ET-B (100%) alone. Immature ganglionic cells in sympathetic ganglia of fetus frequently expressed ET-1 (86%) and ET-B (100%), while ET-A was occasionally detected (28%). Ganglionic cells of mature adult ganglia consistently harbored ET-1 (100%) and, infrequently, ET-3 (21%) or ET-B (29%). Expression of ET-1 and ET-B was closely associated with tumor cell differentiation: the expression frequency of ET-1 or ET-B was 16% or 46% in neuroblastomas; 100% or 88% in ganglioneuroblastomas; and 96% or 92% in ganglioneuromas. In contrast, ET-3 and ET-A showed no association with tumor cell differentiation: the expression frequency of ET-3 or ET-A was 26% or 14% in neuroblastomas; 63% or 13% in ganglioneuroblastomas; and 29% or 21% in ganglioneuromas. In conclusion, ET-1 and ET-B are expressed with differentiation of neuroblastic tumors.

Neural cell adhesion molecule (NCAM) isoform expression is associated with neuroblastoma differentiation status.

BACKGROUND: NCAM is a member of the immunoglobulin superfamily of cell adhesion molecules. While highly expressed on neuroblastoma cells, the relative contribution of the three major NCAM isoforms (120, 140, and 180 kDa) to neuroblastoma biology has not been investigated. METHODS: NCAM protein expression was measured in a neuroblastic tumor tissue microarray (N = 185) by immunohistochemistry. Relative expression of NCAM mRNA isoforms was measured in a panel of 24 human neuroblastomas and compared to fetal and adult human brain using real-time quantitative PCR and Western blot analysis. Associations with clinical and tumor biological co-variates were performed. RESULTS: NCAM protein was detected on all neuroblastic tumors and was highly expressed in all but 7/167 cases. The mRNA species predicted to encode the 120 kDa protein species was the most abundant isoform in adult brain, ganglioneuromas and ganglioneuroblastomas (P = 0.0007), but the mRNA predicted to encode the 180 kDa species was predominant in neuroblastomas (P = 0.043). Microdissected ganglion and neuroblast cells from human primary tumors confirmed these findings. CONCLUSION: Ganglioneuromas and ganglioneuroblastomas express the adhesive 120 kDa NCAM isoform, while neuroblastomas preferentially express the 180 kDa isoform classically involved in cell motility. These data suggest a mechanism for the enhanced metastatic potential of undifferentiated neuroblastomas.

Ganglioneuroblastic differentiation in a primary cutaneous malignant melanoma.

Ganglioneuroblastic differentiation in malignant melanomas is an exceedingly rare event. Although there has been a single report of this occurrence in a metastatic melanoma, divergent ganglioneuroblastic differentiation has not been documented previously in a primary cutaneous lesion of melanoma. The present report describes an unusual case of invasive melanoma arising on the lower leg of a 61-year-old woman. The 16.9-mm thick tumor showed extensive ganglioneuroblastic differentiation, which was confirmed both immunohistochemically and ultrastructurally. Although the prognostic significance of this observation remains uncertain, the unique case reaffirms the potential morphologic diversity of melanomas and suggests a shared histogenetic origin from a common neural crest derivative.

Ret protein expression in adrenal medullary hyperplasia and pheochromocytoma.

Ret is a developmentally regulated tyrosine kinase involved in formation and maintenance of the nervous system. Ret mutations predisposing to pheochromocytomas and medullary thyroid carcinomas occur in multiple endocrine neoplasia (MEN) syndromes 2A and 2B. Biochemical studies have demonstrated overexpression of Ret mRNA and protein in pheochromocytomas compared to normal adrenal medulla. However, the cellular distribution of Ret in the normal human adrenal and in hyperplastic lesions that antecede pheochromocytomas are unclear. The present investigation was undertaken to resolve the histological distribution of Ret in the normal human adrenal, in pheochromocytomas evolving from adrenal medullary hyperplasia in MEN2A and in sporadic pheochromocytomas. Ret expression was studied by immunohistochemistry using both a polyclonal and a monoclonal antibody, with confirmation by immunoblotting of representative cases. Only occasional cells stained for Ret in the normal adrenal, consistent with the distribution in adult adrenals of other species. Heterogeneous, progressively increased Ret expression was observed during the evolution of pheochromocytomas. In both normal and neoplastic adrenal, the most intense immunoreactivity was observed in cells with neuron-like features. Our finding that Ret is not expressed at high levels in the early stages of disease suggests that elucidation of mechanisms that regulate Ret expression is required for understanding the pathobiology of MEN2A. The association of high-level Ret expression with neuronal morphology suggests that the variable overexpression of Ret in pheochromocytomas might in part be an epiphenomenon, reflecting the known phenotypic plasticity of these tumors.

Undifferentiated ganglioneuroblastoma in a sheep.

Ganglioneuroblastoma, presumably originating from the adrenal medulla, was found in an 18-month-old sheep. Histologically, the tumour was mainly composed of undifferentiated neuroblasts with neuropil and occasional ganglion cells. The morphological and immunohistochemical features with respect to intermediate filament proteins and the neuroendocrine nature of the tumour are described. The neoplastic cells were positive for neuron-specific enolase, synaptophysin and vimentin.

Evidence of chromaffin oxygen sensing in neuroblastoma.

With the aid of IGF2 and VEGF in situ hybridization; tyrosine hydroxylase, chromogranin A, and Ki67 immunohistochemistry; and TUNEL staining applied to a large series of clinical neuroblastomas and to an animal model, we show here that stroma-poor neuroblastomas show evidence of chromaffin differentiation similar to that of type 1 small intensely fluorescent (SIF) cells and that this occurs in a vascular-dependent fashion, indicating a role for local tumor hypoxia in the differentiation process.

So-called malignant and extra-ventricular neurocytomas: reality or wrong diagnosis? A critical review about two overdiagnosed cases.

Central neurocytoma (CN) is described as a rare intra-ventricular benign neuronal tumor of the brain. Two primary tumors first diagnosed as malignant and extra-ventricular neurocytomas are reported here. Histologically, the tumor of the first patient, a forty-one-year-old man, consisted of monotonous cells with round nuclei, but no fibrillar background. The second tumor, in a nineteen-year-old girl, showed areas of moderately pleomorphic round cells, with numerous rosettes and ganglion cell differentiation, in an abundant fibrillary network. Both presented calcifications. Mitoses were more frequent in recurrences and spinal locations than in the primaries. All tumors stained strongly for synaptophysin, and GFAP was partly positive in the first case only. Patients received post-surgical radiotherapy and were still alive eight and six years, respectively, after initial surgery. The interpretation of atypical cases, such as ours is not easy: the diagnoses finally retained were oligodendroglioma in the first case and ganglioneuroblastoma in the second case. Furthermore, neurocytomas atypical either by their unusual topographical or histological presentation or by their poor prognosis, have been frequently entitled in this way on synaptophysin positivity. So, we were prompted to reassess the entity of CN, seventeen years after the first description, to re-appreciate the reality of anatomo-clinical variants and to discuss the value of synaptophysin positivity in these tumors. In conclusion, it seems preferable to individualize true classical CN, which has a favorable outcome, from so-called extra-ventricular, atypical and anaplastic, clinically malignant neurocytomas for which complementary treatment is required.

Divergent differentiation in neuroendocrine tumors of the adrenal gland.

Composite tumors of the adrenal medulla usually consist of pheochromocytoma admixed with ganglioneuroma or ganglioneuroblastoma. These neoplasms reflect phenotypic plasticity shown by primitive sympathetic cells and mature chromaffin cells in vitro. They may give rise to metastatic neuroblastoma in adults and may cause signs and symptoms attributable to both catecholamine and neuropeptide production. Schwann cells and sustentacular cells are typically numerous in these tumors but it is not known whether they are neoplastic. Immunohistochemical staining for catecholamine biosynthetic enzymes, secretory vesicle proteins and S-100 protein tends to recapitulate staining of the normal adrenal medulla or sympathetic ganglia. Sparsity of chromogranin A in the cell bodies of immature and mature neurons is a diagnostically useful characteristic.

The RNA component of telomerase as a marker of biologic potential and clinical outcome in childhood neuroblastic tumors.

BACKGROUND: Telomerase is a ribonucleoprotein enzyme associated with cellular immortality that may be useful in determining the biologic potential of a tumor. Neuroblastoma (NB), ganglioneuroblastoma (GNB), and ganglioneuroma (GN) are neuroblastic tumors (NTs) that exhibit a spectrum of histologic features and are often associated with unpredictable behavior and clinical outcome. METHODS: The authors investigated the expression of the RNA component of human telomerase (hTR) by in situ hybridization in 32 cases of NTs (including 24 NBs, 4 GNBs, and 4 GNs), using [35S]-UTP labeled single stranded sense and antisense RNA probes. Eight NBs were early stage, 12 NBs were advanced stage, and 4 NBs were Stage IVS, a widely metastatic variant associated with an excellent clinical prognosis. Four NBs had N-myc amplification. In addition, the authors compared a proliferation marker, MIB-1, with hTR expression in a subset of tumors. RESULTS: Thirty of 32 NTs expressed hTR, with expression varying from weak (1+) to intense (4+). Most advanced stage NBs (9 of 12) and only 2 of 8 early stage NBs had moderate to intense (2 to 4-) expression of hTR. The remaining early stage tumors (6 of 8) and 3 of 12 advanced stage NBs had absent or weak expression of hTR (0 to 1+). There was no disease progression in any of the patients with absent or weak expression of hTR. In contrast, 8 tumors (from 7 patients) with moderate to intense expression of hTR in the tumor sections had adverse clinical outcomes, including recurrence, persistent disease, or death. hTR expression in all the Stage IVS tumors was weak, despite the fact that the patients had widely metastatic disease at presentation. The mean hTR score of 3.1 for NBs associated with an adverse outcome (n = 8) was significantly different from the mean hTR score of 1.3 for NBs associated with a favorable outcome (n = 16), P < 0.001. hTR expression in the GNB/GNs was limited to the ganglion cells only; Schwann cells were negative for hTR expression. Stage IVS tumors, which are associated with an excellent outcome, had high MIB-1 but weak hTR expression, indicating that the latter may be a better discriminator of true biologic potential and that hTR levels do not always correlate with cell proliferation. CONCLUSIONS: Increased hTR expression may reflect the potential for aggressive behavior within the spectrum of NTs; conversely, down-regulation of hTR may be useful in identifying subsets with limited capacity for progression and a favorable prognosis.

Cerebellin and cerebellin mRNA in the human brain, adrenal glands and the tumour tissues of adrenal tumour, ganglioneuroblastoma and neuroblastoma.

The expression of cerebellin and cerebellin mRNA was studied by radioimmunoassay and Northern blot analysis in the human brain, adrenal gland and the tumour tissues of adrenal tumour, ganglioneuroblastoma and neuroblastoma. Immunoreactive cerebellin was detected in every region of brain studied, with the highest concentrations found in the hemisphere of the cerebellum (424.2 +/- 12.6 pmol/g wet weight, n = 6, mean +/- S.E.M.) and the vermis of the cerebellum (256.8 +/- 30.5 pmol/g wet weight). Immunoreactive cerebellin was also detected in the pituitary (8.2 +/- 1.8 pmol/g wet weight), the spinal cord (3.3 +/- 0.3 pmol/g wet weight) and the normal parts of adrenal glands (2.98 +/- 0.37 pmol/g wet weight, n = 9) and some tumour tissues, such as phaeochromocytomas, cortisol-producing adrenocortical adenomas, ganglioneuroblastomas and neuroblastomas. Northern blot analysis showed that cerebellin mRNA was highly expressed in the hemisphere and vermis of the cerebellum. Cerebellin mRNA was also expressed in other regions of the brain and the tumour tissues of phaeochromocytoma, cortisol-producing adrenocortical adenoma, ganglioneuroblastoma and neuroblastoma. Immunocytochemistry of the normal adrenal gland showed that immunoreactive cerebellin was localized in the adrenal medulla. The present study has shown the expression of cerebellin and cerebellin mRNA, not only in the cerebellum but also in other regions of the brain and some tumours, such as cortisol-producing adrenocortical adenoma, phaeochromocytoma and neuroblastoma. These findings suggest possible pathophysiological roles of cerebellin peptides, not only in the cerebellum, but also in the extra-cerebellar tissues.

Ganglioneuroblastoma of the thymus: an adult case with the syndrome of inappropriate secretion of antidiuretic hormone.

A 61-year-old woman was admitted to the hospital because of general fatigue. Laboratory examinations showed hyponatremia, plasma hypo-osmolarity, and inappropriate increased concentration of the plasma antidiuretic hormone (ADH) in the presence of concentrated urine. Magnetic resonance imaging revealed a mass lesion in the anterior mediastinum. An extended thymectomy was performed under the diagnosis of thymoma with the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). Histologically the tumor was located in the thymic tissue and was diagnosed as ganglioneuroblastoma. Immunohistochemical studies showed the existence of ADH in the tumor cells. To the knowledge of the authors, this is the first case of ganglioneuroblastoma of the thymus with SIADH.

IGF2 expression is a marker for paraganglionic/SIF cell differentiation in neuroblastoma.

Neuroblastoma is a childhood tumor of the sympathetic nervous system. Observations in the Beckwith-Wiedemann syndrome suggest that sympathetic embryonal cells with an abundant expression of the insulin-like growth factor 2 gene (IGF2) may be involved in the genesis of low-malignant infant neuroblastomas. We have therefore compared the cell type-specific IGF2 expression of the human sympathetic nervous system during early development with that of neuroblastoma. An abundant expression in normal sympathetic tissue was specific to extra-adrenal chromaffin cells, ie, paraganglia and small intensely fluorescent (SIF) cells, whereas sympathetic neuronal cells were IGF2-negative. A subpopulation of neuroblastomas expressed IGF2, which correlated with an early age at diagnosis, an extra-adrenal tumor origin, and severe hemodynamic signs of catecholamine secretion. Histologically IGF2-expressing tumors displayed a lobular growth pattern, and expression was restricted to the most mature and least proliferative cells. Typically, these cells were morphologically and histochemically similar to paraganglia/SIF cells and formed distinct ring-like zones in the center of the lobules around a core of apoptosis-like tumor cells. The similarities found between IGF2-expressing neuroblastoma cells and paraganglia/SIF cells in terms of histological features, anatomical origin, and age-dependent growth suggest a paraganglionic/SIF cell lineage of most infant tumors and also of extra-adrenal tumors diagnosed after infancy. Furthermore, since paraganglia/SIF cells undergo postnatal involution, the same cellular mechanism may be responsible for spontaneous regression in infant neuroblastoma.

Immunohistochemical analysis of proliferating cell nuclear antigen expression in human neuroblastoma.

Proliferative cell nuclear antigen (PCNA) is a cell-cycle-related nuclear protein that is maximally elevated in late G1 and S phase of proliferating cells. In this study, PCNA was identified immunohistochemically using paraffin section in 67 human neuroblastomas. Percentage of the PCNA-positive nuclei (PCNA index: PCI) ranged from 0% to 75%. There were significant relations between the PCNA expression and mitotic karyorrhexis index (MKI), histological classification, cell concentration, tumor weight, clinical stage, local invasion, lymph node metastasis, liver metastasis, or DNA ploidy. PCI was significantly low in patients who received aggressive chemotherapy before surgery. Patients with PCI higher than 30% showed a worse survival rate compared with those with PCI lower than 10% (P < .01). High PCI significantly related with poor survival, so that PCI may be an independent prognostic factor in neuroblastoma. Although further studies are required, PCNA immunostaining may be useful for assessing proliferating activity and for providing prognostic information in human neuroblastoma.

Ret-oncogene expression correlates with neuronal differentiation of neuroblastic tumors.

An antibody to the ret proto-oncogene product (RET) was raised and applied to formalin-fixed, paraffin-embedded neuroblastic tumors (NBTs) to investigate its usefulness in diagnosis and evaluation of cell differentiation. In normal neural crest-derived tissues, most ganglion cells were moderately stained while large ganglion cells were weakly stained. In NBTs, the intensity of the staining in moderately differentiated neuroblasts and small ganglion cells was more prominent than in undifferentiated neuroblasts, while the cytoplasm of large ganglionic cells was weakly stained as in normal ganglion cells. The RET immunoreactivity was compared with that of nine neural and neuroendocrine markers. The results revealed a parallelism with the protein gene product 9.5 (PGP9.5), neuron specific enolase (NSE) and NF-150 kD (NF = M). These findings indicated that the RET immunoreactivity was correlated with ganglionic differentiation and maturation. Thus, RET was considered to be a new marker that would be implemented in diagnosis and estimation of neuronal differentiation of NBTs.

Differential expression of beta 1, beta 3 and beta 4 integrins in sarcomas of the small, round, blue cell category.

Integrins are a large and complex family of membrane spanning alpha beta heterodimeric cell surface glycoproteins mediating cell/cell and cell/matrix interactions. Small, round, blue cell sarcomas (SRBCS) are a group of poorly differentiated tumours of various and in part uncertain histogenesis displaying similar cytomorphology. Among them are rhabdomyosarcomas (RMS), ganglioneuroblastomas [(G)NB], primitive peripheral neuroectodermal tumours (pPNET) and Ewing's sarcomas (ES). Thirty-two SRBCS were studied immunohistochemically for the distribution of beta 1, beta 3 and beta 4 integrins in situ. We found complex and to some extent differential patterns of beta 1, beta 3 and beta 4 integrin subunit expression in different types of SRBCS: all of the sarcomas studied were consistently beta 1+, beta 4-, alpha 2-. Four of nine RMS were completely negative for all other integrin subunits studied while one RMS was alpha 5+ throughout and three RMS were focally alpha 5+. Three RMS expressed the alpha 6 and alpha v chains. In contrast to RMS, pPNET and ES, all of which were alpha 1-, alpha 3-, (G)NB were alpha 3+ and frequently co-expressed alpha 1. The eight pPNET and seven ES studied showed a similarly restricted integrin profile that was limited to the expression of beta 1 and alpha 5 in nearly all cases. In summary, RMS were beta 1+, alpha 1-, alpha 3- and heterogeneously expressed alpha 5 and alpha 6. (G)NB were generally beta 1+, alpha 1+, alpha 3+, alpha 5-, alpha 6-. pPNET and ES were beta 1+, alpha 1-, alpha 3-, alpha 5+, alpha 6-. The data illustrate a complex expression pattern of various integrins in SRBCS, a differential expression pattern of some of the integrin subunits among different types of SRBCS and almost identical integrin profiles in pPNET and ES.

An immunohistochemical study of peripheral neuroblastoma, ganglioneuroblastoma, anaplastic ganglioglioma, schwannoma and neurofibroma in cattle.

Immunohistochemical analysis of five paraffin wax-embedded neoplasms was performed to elucidate the characteristics of bovine nervous-tissue tumours. In case 1 (peripheral neuroblastoma), the neoplastic tissue was characterized by the formation of true and Homer-Wright rosettes and the existence of neuron-specific enolase. The neoplastic cells were possibly more immature than those of common neuroblastomas, because similar features are observed in human malignant neuroepitheliomas. The neoplastic cells in case 2 (ganglioneuroblastoma) ranged from large cells with abundant neurofilaments to immature small cells, rarely with neurofilaments or glial fibrillary acidic protein (GFAP). Such expression suggests the presence of pluripotential cells. The neoplastic tissue in case 3 (anaplastic ganglioglioma) was strikingly polymorphous, and had five elements; neuronal, astrocytic, oligodendrocytic, spindle cell and small oval cell. The neoplastic neurocytes and astrocytes were, respectively, characterized by neurofilament and GFAP positivity. The neoplastic oligodendrocytes made a honeycomb appearance, and the neoplastic spindle cells and small oval cells were considered to be less differentiated. The tumours of cases 2 and 3, which contained poorly differentiated cells and revealed both neuronal and glial differentiation, may be specific to calves. In case 4 (schwannoma), almost all the neoplastic cells were positive for S100 protein, while S100-negative fibroblasts were present in many areas of case 5 (neurofibroma). These two tumours were readily distinguished histologically and immunohistochemically.

Expression of bcl-2 gene product in neuroblastoma.

The expression of bcl-2 is associated with inhibition of apoptosis and prolonged cell survival. The purpose of this study was to examine the immunoreactivity of neuroblastoma and ganglioneuroblastoma tissue samples to the bcl-2 gene product in order to see if it was related to prognosis. BCL-2 protein was detected in all the 46 formalin-fixed, paraffin-embedded samples from 34 patients representing all clinical stages and sites of involvement. Immunopositivity was observed in tumours from the primary and metastatic sites. Moreover, it was demonstrated in the pre-chemotherapy and the post-chemotherapy samples from six cases with stage 4 disease. It was observed in neuroblasts in various stages of differentiation. A small proportion of undifferentiated neuroblasts were negative. As BCL-2 oncoprotein was present in all the cases irrespective of the clinical outcome, it does not appear to be one of the factors influencing prognosis.

Pituitary adenylate cyclase activating polypeptide (PACAP)-like immunoreactivity in ganglioneuroblastoma and neuroblastoma.

Pituitary adenylate cyclase activating polypeptide (PACAP) is a 38 amino acid peptide originally isolated from ovine hypothalamus. It has a potent stimulatory action on adenylate cyclase in the rat pituitary. The presence of PACAP was studied in the tumor tissues of ganglioneuroblastoma and neuroblastoma by radioimmunoassay and immunocytochemistry. Immunocytochemical studies showed positive immunostaining in 4 out of 7 ganglioneuroblastomas and 4 out of 6 neuroblastomas. Immunoreactive PACAP concentrations in tissues of 3 ganglioneuroblastomas ranged from 14.5 to 27.8 pmol/g wet weight (20.0 +/- 5.7 pmol/g wet weight, mean +/- S.D.) and the concentration in one neuroblastoma tissue was 111.0 pmol/g wet weight. Reverse phase high performance liquid chromatography of the tumor tissue extract of ganglioneuroblastoma showed a peak eluting in the position of PACAP1-38 and smaller broad peaks eluting later. These results indicated that high concentrations of immunoreactive PACAP were present in the tumor tissues of ganglioneuroblastoma and neuroblastoma, and suggest the possibility that this peptide plays a pathophysiological role in some ganglioneuroblastomas and neuroblastomas.