Histopathologic prognostic factors in neuroblastic tumors: definition of subtypes of ganglioneuroblastoma and an age-linked classification of neuroblastomas

Prognostic value of N-myc oncogene amplification and S-100 protein positivity in children with neuroblastic tumors

Data on 43 neuroblastic tumors (30 neuroblastomas and 13 ganglioneuroblastomas) obtained from 22 untreated and 21 pretreated children, were analyzed to determine the correlation between N-myc oncogene amplification and immunohistochemically identified S-100 protein positivity. Sixteen patients in whom the tumor showed significant amplification of N-myc (more than ten copies) died, irrespective of S-100 protein positivity and other conventional factors. Among 27 patients with low amplification of N-myc (less than ten copies), the estimated progression-free survival for those whose tumors had numerous S-100 protein-positive cells (P group), and few or no positive cells (N group) was 75% and 17%, respectively (p < 0.0001). Thus, in addition to N-myc oncogene amplification as a reliable indicator of outcome, S-100 protein positivity should be useful for prediction of prognosis in children with neuroblastic tumors showing low amplification of N-myc. Correlations among these results and other clinical factors are briefly discussed.

Prognostic importance of DNA flow cytometrical, histopathological and immunohistochemical parameters in neuroblastomas

In 42 tumour samples of human neuroblastoma, histological classification by differentiation (Shimada) was significantly correlated with strong positivity for neuron-specific enolase (NSE) and inversely correlated with rosette formation. Most ganglioneuroblastomas were positive for S-100 protein and reacted strongly with NSE antibody. Histological signs of high proliferative activity included intermediate or high mitosis-karyorrhexis index, necrosis and lack of calcification, which were significantly correlated with each other. Flow cytometric DNA analysis demonstrated that 88% of the tumour samples had DNA aneuploid stem lines. High S phase fraction (greater than or equal to 0.20) was significantly correlated with necrosis and lack of calcification. Univariate analysis of prognosis for 26 patients whose tumour samples were obtained before adjuvant treatment showed that five factors were significantly related to a better outcome: early stage of the disease (stages I, II, IV-S), S phase fraction less than 0.20, favourable Shimada histology, positivity for S-100 protein, and strong positivity for NSE. In multivariate analysis, only S phase fraction or stage of disease remained significantly associated with prognosis. DNA index did not correlate with prognosis in this study.

Clinical impact of chromosome 1 aberrations in neuroblastoma: a metaphase and interphase cytogenetic study

Neuroblastoma tumors are characterized by aberrations of chromosome 1. Rapid detection of these chromosomal aberrations at diagnosis could give important clues to outcome and therapy. We attempted to detect numerical and structural aberrations of chromosome 1 not only by classical metaphase cytogenetics but also by interphase cytogenetics in order to overcome difficulties of karyotyping due to diminished metaphase quality and quantity in primary neuroblastoma samples. Karyotypic changes of chromosome 1 in 53 primary neuroblastomas were evaluated. In addition, we successfully performed interphase cytogenetics using single and double in situ hybridization procedures with chromosome 1-specific repetitive DNA probes on nuclei preparations obtained from 46 and 20 tumors, respectively. Polysomies of structurally normal chromosomes 1 were predominantly seen in tumors with good prognosis, whereas deletions of 1p material were nearly exclusively confined to progressive tumors. Numerical and structural chromosome 1 aberrations as studied by metaphase and interphase cytogenetics are thus valuable prognostic markers in neuroblastoma.

Modulation of neuroblastoma cell differentiation by the extracellular matrix

The effect of a complex in vitro synthesized extracellular matrix (ECM) and its components on growth and phenotypical differentiation of a human neuroblastoma (NB) cell line (HTLA230) was investigated. Rat smooth-muscle-cell (R22CIF)-derived ECM composed of collagen, glycoproteins, and glycosaminoglycans (GAGs) promoted spontaneous neurite outgrowth of HTLA230 cells but did not alter their growth kinetic or cloning efficiency as compared with cells seeded onto gelatin-coated dishes. The matrix significantly enhanced, quantitatively and qualitatively, the responsiveness of HTLA230 cells to retinoic acid (RA), and a substantially reduced growth rate was observed in the presence of RA with cells grown on the ECM. Biochemical modification of the composition of the R22CIF-matrix by trypsin digestion and/or high-salt extraction (4 M guanidinium) demonstrated that the ratio of chondroitin sulfate to hyaluronic acid (HA) present in the ECM determines the capacity of the matrix to promote NB differentiation. A human fibroblast (T-1)-derived ECM, which has a biochemical composition of the GAG component similar to that of the trypsinized R22CIF-matrix, but which has a high amount of glycoproteins, confirmed these results. Nerve-growth-factor (NGF)-induced differentiation in a variant HTLA 230 cell line was inhibited when cells were grown on an ECM with a low ratio of chondroitin sulfate/HA. The composition of the ECM thus modulates the responsiveness to various differentiation-inducing agents and alters the phenotype of NB cells.

Bi-modal differentiation pattern in a new human neuroblastoma cell line in vitro

We have isolated a human neuroblastoma (NB) cell line, HTLA230, from the bone-marrow aspirate of a patient with stage-IV disease. Subcutaneous tumors after inoculation of HTLA230 cells into nude mice were composed of primitive neuroblasts which rarely contained neuro-secretory granules. Cytogenetic studies of the cell line demonstrated 2 distinct populations of cells with common chromosomal markers. Stable sub-clones with a differentiated or undifferentiated cell morphology were isolated, demonstrating phenotypical heterogeneity of the HTLA230 parental cell line. Treatment with retinoic acid (RA) induced extensive neurite outgrowth in the parental cell line and in phenotypically differentiated sub-clones, but rarely in undifferentiated ones. Long-term treatment with RA was not associated with down-modulation of mycN-gene expression, which could be achieved only in cultures treated additionally with aphidicolin, a DNA-synthesis inhibitor, thus eliminating growing NB cells. A RA resistant subclone (CI-5) was isolated from parental HTLA230 cells grown at clonal cell density. Cells originally showed a homogeneously differentiated morphology; however, flat cells (F-cells) appeared with time and were subsequently separately propagated. Transdifferentiation of isolated F-cells into cells with neuron-like (N-cell) morphology was observed. Immunohistochemical analysis demonstrated that F-cells had lost the expression of neuronal markers, including HNK-I and A2B5, and expressed the intermediate filament, vimentin. Furthermore, F-cells showed high incorporation of [methyl-3H] thymidine (3H-TdR) by autoradiography but no mycN protein could be detected, although present in the parental cell line. These results then suggest that the isolated NB cell line and the RA-resistant variant line represent an excellent in vitro model with which the bi-modal differentiation pathway of NB can be analyzed on a molecular biological level.

Characteristics and management of patients with fetal neuroblastoma

At 35 weeks 6 days of gestational age, ultrasound evaluation of the fetal abdomen showed a mixed cystic mass in the superior pole of the left kidney. The mass was suspected to be an adrenal hemorrhage or neuroblastoma. The diagnosis was fetal neuroblastoma. Differential diagnosis enabled the fetal neuroblastoma to be distinguished from adrenal hemorrhage. The parameters of diagnosis of fetal neuroblastoma include no specific ultrasonographic pattern, lack of palpability, and no tumor markers. However, certain features do characterize fetal neuroblastoma, such as little metastases, complete resection at operation, and excellent prognosis. In cases of suspected neuroblastoma, a laparotomy performed as soon as possible is generally regarded as the best course of treatment. Nonetheless, biological analyses of the tumor may prove in the future to be necessary for determining whether or not laparotomy is the best treatment.

Therapeutic significance of surgery in advanced neuroblastoma: a report from the study group of Japan

The role of surgery was evaluated in 19 stage III and 102 stage IV neuroblastoma patients, all of whom were treated with intensive induction chemotherapy by the Study Group of Japan between January 1985 and March 1990. For stage III neuroblastoma, surgical intervention at the primary site was performed in 18 of the 19 patients, 9 during and 9 after the first three cycles of A1 regimen, consisting of high-dose cyclophosphamide, vincristine, THP-adriamycin, and cis-platinum. Gross complete resection of primary tumor and regional lymph nodes was feasible in 17 of the 19 patients (89%), and the survival rate for the 17 patients were 79%, 70%, and 70% at 2 years, 3 years, and 4 years, respectively. For stage IV, surgical intervention at the primary site was performed in 92 of the 102 patients (90%): 30 cases during the first 3 cycles of A1 chemotherapy and 62 cases after that, with gross complete resection accomplished in 81 of the 102 patients (79%). The 81 patients with gross complete resection achieved had a better prognosis than those 11 patients with partial resection (P less than .05). Overall survival rate was 62% at 2 years for 27 patients who underwent complete resection after 3 cycles of A1 when resolution of all metastases was obtained, whereas the survival was 52% at 2 years for 31 patients who similarly underwent complete resection but when evidence of persistent metastases was present. Patients in whom the ipsilateral kidney was preserved at surgery had an outcome superior to that of those with associated nephrectomy (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Recommendations for modification of terminology of neuroblastic tumors and prognostic significance of Shimada classification. A clinicopathologic study of 213 cases from the Pediatric Oncology Group

To develop consistency in terminology and pathologic criteria, the authors reviewed the literature and 213 cases of neuroblastic tumors (NT) registered with Pediatric Oncology Group (POG) protocols 8104 and 8441. The patients were given standardized therapy stratified according to POG stage and patient age, and four or more histologic sections of primary tumor resected before therapy were available in each of these 213 cases. All stages were represented. The recommended nomenclature combines conventional terms and criteria with those used by Bove and McAdams and Shimada et al. The main features of the recommended nomenclature are as follows: (1) the terms neuroblastoma (NB) and ganglioneuroblastoma (GNB) are retained instead of stroma-poor NB and stroma-rich NB, recommended by Shimada et al.; (2) undifferentiated NB is considered a subtype separate from poorly differentiated NB; and (3) the term GNB is used only when there is a predominant ganglioneuromatous component admixed with the minor neuroblastomatous component. With the use of these criteria and terms, the Shimada classification was determined in the 213 cases. The results showed that, even after stratification for age, POG stage, and primary site, there is a statistically significant difference in survival rate between favorable histologic and unfavorable histologic prognostic subgroups. The authors recommend that definitive prognostic categorization of an NT according to Shimada classification should be done only when adequate histologic material is available from a primary tumor resected before any other therapy. Categorization done on histologic material from small biopsy specimens, previously treated primary tumors, or metastatic sites should be considered tentative.

Age-linked prognostic categorization based on a new histologic grading system of neuroblastomas. A clinicopathologic study of 211 cases from the Pediatric Oncology Group

Histologic sections (minimum of four sections per patient) from 211 patients with neuroblastoma were reviewed. The tumors were resected before therapy, which was standardized according to age and stage. Low mitotic rate (MR) (less than or equal to ten per ten high-power fields) and calcification emerged as the most significant prognostic features after statistical analysis by stepwise log-rank tests (P less than 0.0001 and P = 0.0065, respectively). Histologic Grades 1, 2, and 3 were defined on the basis of the presence of both, any one, or none of these two prognostic features, respectively (Grade 3 had absence of low MR, i.e., these tumors had high MR [greater than ten per ten high-power fields]). Statistically significant differences in survival were observed in the grades after adjusting for age and stage (P less than 0.001). The degree of differentiation, although significant by itself, was no longer significant after adjusting for the grades. Age groups (less than or equal to 1 versus greater than 1 year of age), which also emerged as an independent prognostic feature (P less than 0.001), were linked with the grades to define two risk groups as follows: (1) a low-risk (LR) group consisting of patients in both age groups with Grade 1 tumors and patients 1 year of age or younger with Grade 2 tumors and (2) a high-risk (HR) group consisting of patients older than 1 year of age with Grade 2 tumors and patients in both age groups with Grade 3 tumors. The difference in survival between LR (160 cases) and HR groups (51 cases) was statistically significant (P less than 0.001). Concordance between these LR and HR groups and the Shimada classification was observed in 84% of cases. The new histologic grading system has the following advantages: (1) use of familiar terminology and histologic features in the grading system and (2) relative ease of assessment because the degree of differentiation does not need to be determined. The grading system should be tested on a new data set with an appropriate histologic sample of similar size to confirm these results.

Three neuroblastoma cell lines established from consecutive samples of one patient which show distinct morphologic features, MYCN amplification, and surface marker expression

Three neuroblastoma cell lines established from tumor samples obtained from one patient are described. The three lines were derived from bone marrow aspirates taken at diagnosis, and 13 and 15 months later. The origin of the cell lines PER-106, PER-107, and PER-108 from malignant neuroblasts was confirmed by electron microscopy studies, surface marker analysis, and assessment of MYCN amplification. Cell lines PER-107 and PER-108, which were established from tumor samples obtained at the time of progressive disease, have significantly shorter doubling times than PER-106 and grow mainly substrate-adherent, while cell line PER-106 (established from sample obtained at diagnosis) consists of small round neuroblastic cells which form large aggregates in suspension culture. The electron microscopy studies revealed distinctive neuroblast-like ultrastructure in all cell lines. The MYCN copy number was amplified (greater than 10 copies) in the established cell lines and in the fresh tumor samples and the relative abundance of MYCN RNA in the cell lines correlated roughly with the extent of the MYCN gene amplification. However, distinct phenotypic differences can be demonstrated among these three lines, which provide a model for the further examination of this highly malignant tumor. Detection of MYCN amplification by chromosomal in situ hybridization was performed on this set of cell lines, as reported by McRobert et al. (this issue, pages 128-134).

Length of telomeric repeats in neuroblastoma: correlation with prognosis and other biological characteristics

Telomeres are the physical ends of eukaryotic chromosomes. In view of reports of the reduction of telomeric repeats in human malignant tumors, we measured the lengths of telomeric repeats in 55 primary neuroblastomas. The average lengths of telomeric repeats in these tumors fell in a wide range (from 1.1 kb to more than 23 kb) relative to those in ganglioneuromas and normal peripheral mononuclear cells. The reduction of telomeric repeats was significantly correlated with advanced stages of tumor development, poor prognosis, and increased S-phase fractions in tumor cells. On the other hand, three cases of Stage IV-S tumors showed the reduction of telomeric repeats and low percentage of S-phase fractions. These Stage IV-S patients had a good prognosis with spontaneous regression of metastatic tumors.

Neuroendocrine tumors of the nasal cavity: an ultrastructural and morphometric study of 24 cases

A series of 24 small cell nasal tumors with neuroendocrine differentiation was studied by electron microscopy, and the numbers of secretory granules and cell junctions were assessed. To investigate the relationship between the extent of dendrite formation and the behavior of the tumors, the size of the tumor cells and the area occupied by dendritic processes were determined for each tumor by morphometric analysis performed on low-magnification electron micrographs. A positive correlation was demonstrated between the dendritic area index and the survival of the patients (P = 0.017). Neither the number of secretory granules nor the frequency of cell junctions was prognostically significant.

P-glycoprotein expression as a predictor of the outcome of therapy for neuroblastoma

BACKGROUND AND METHODS

Multidrug resistance in chemotherapy for cancer is characterized by increased genetic expression of P-glycoprotein, which acts as an ATP-dependent drug-efflux pump. To determine whether P-glycoprotein levels are of prognostic value in such cases, we measured these levels immunohistochemically in a retrospective study of sequential tumor samples from 67 children with neuroblastoma.

RESULTS

P-glycoprotein was not detected in pretreatment samples from either of the 2 patients with Stage I disease, any of the 21 with Stage II disease, or any of the 8 with Stage IVS disease, but it was detected in the samples from 1 of the 17 patients with Stage III disease (6 percent) and 12 of the 19 with Stage IV disease (63 percent). Of the 44 patients with nonlocalized neuroblastoma (Stage III, IVS, or IV), 26 of the 31 who were negative for P-glycoprotein had a complete response to primary treatment, as compared with 6 of the 13 who were positive for P-glycoprotein (84 percent vs. 46 percent, P = 0.0232 by Fisher's exact test). Log-rank analysis of outcome, with simultaneous stratification according to tumor stage and age, showed that the group that was negative for P-glycoprotein had significantly longer relapse-free survival (P = 0.0011) and overall survival (P = 0.0373) than the group that was positive.

CONCLUSIONS

Expression of P-glycoprotein before treatment may predict the success or failure of therapy for nonlocalized neuroblastoma. Neuroblastoma may be a promising tumor to treat with anticancer drug therapy combined with a chemosensitizing agent capable of reversing P-glycoprotein-mediated multidrug resistance.

Treatment for stage III-IV neuroblastoma patients: initial response to chemotherapy evaluated by biochemical parameters

Fourteen patients with stage III-IV neuroblastoma were treated with alternating combination chemotherapy consisting of (a) VP16/cisplatin and (b) doxorubicin/vincristine/cyclophosphamide. The initial response to induction chemotherapy, especially to VP16/cisplatin was evaluated by determining t 1/2 for urinary vanillylmandelic acid (VMA), homovanillic acid and serum neuron specific enolase (NSE). The period prior to normalization of these parameters was also determined. The patients could be classified as 7 rapid responders, with less than 3 weeks of t 1/2 VMA, or t 1/2 NSE, and 7 slow responders longer than 4 weeks of t 1/2 VMA. An analysis of the data indicates that an initial rapid response correlated with subsequent high complete response rate, but did not necessarily predict better prognosis in these patients.

Expression of integrin receptors on 45 clinical neuroblastoma specimens

Immunohistological expression of integrins has been analyzed on 45 neuroblastoma specimens representative of the different clinical and histological forms of the tumor. None of the specimens expressed the alpha 5 chain of the integrins. The beta 1 chain was expressed on all specimens, the alpha 1 chain on 44 specimens and the alpha 3 chain on 42; the 4 specimens which lacked alpha 1 or alpha 3 were stage-4 neuroblastomas. The alpha 2 chain was expressed on 18 specimens, and the alpha 6 chain on 17; 15 reacted with both. Their reactivity was related to the maturation of the tumor rather than the stage of the disease: they were expressed on low-grade, well-differentiated specimens; stage 3-4 neuroblastoma specimens analyzed at diagnosis were negative, but usually expressed both chains when analyzed after in vivo differentiation by chemotherapy. alpha v reacted with 18 specimens and beta 3 with 12, without strict relation with the stage of the disease and/or its degree of differentiation; 9 well-differentiated specimens expressed the beta 4 chain; only 4 well-differentiated specimens expressed the alpha 4 chain. The 4 specimens which lacked alpha 1-beta 1 or alpha 3-beta 1 expression had n-myc amplification, whereas those which expressed either alpha 4, beta 4, beta 3 or alpha v had no amplification. Furthermore, the expression of the 3 heterodimers alpha 4-beta 1, alpha v-beta 3 and alpha 6-beta 4 was essentially observed on primary tumors which developed in the mediastinum. The expression of alpha 2-beta 1 and alpha 6-beta 1 was observed on both n-myc-positive and -negative specimens. beta 1 and alpha 3 were diffusely expressed on all counterparts of these tumors, from undifferentiated neuroblasts to ganglion and Schwann cells. The alpha 1 chain reacted with undifferentiated and intermediate neuroblasts as well as with Schwann cells, but ganglion cells were negative. alpha 2 and alpha 6 chains were negative on undifferentiated neuroblasts, variably expressed on intermediate neuroblasts, and restricted to Schwann cells in ganglioneuroma. The expression of alpha 4 and beta 4 was restricted to Schwann cells. alpha v and beta 3 occasionally reacted with undifferentiated and intermediate neuroblasts; alpha v was strongly positive on Schwann cells but negative on ganglion cells, whereas beta 3 was positive on both neuronal and non-neuronal populations.

A significant association of Ha-ras p21 in neuroblastoma cells with patient prognosis. A retrospective study of 103 cases

To evaluate biologic characteristics of neuroblastoma, the authors examined the expression of Ha-ras gene (Ha-ras p21) in 103 primary tumors obtained at the time of diagnosis. Higher expression of the Ha-ras p21 in tumor cells showed a significant association with lower clinical stage of the tumor at diagnosis (chi-square = 35.418, degrees of freedom [df] = 9, P less than 0.001) and survival of the patients (chi-square = 37.111, df = 3, P less than 0.001). Thirty-six (84%) of 43 patients with decreased Ha-ras p21 expression died of aggressive disease. The Ha-ras DNA was examined in the 32 tumors by Southern blot analysis. Neither augmentation nor deletion of the Ha-ras DNA was observed. Amplification of the N-myc DNA was also examined in 43 cases in comparison with Ha-ras p21 expression. N-myc amplification was detected in 12 (55%) of 22 patients who died, and 19 (86%) of the 22 patients showed a low expression of the Ha-ras p21 in tumor cells. Eighteen (86%) of 21 survivors showed a high expression of the Ha-ras p21. The expression of Ha-ras p21 was thought to be a clinically important marker for prognosis in children with neuroblastoma.

Surgical management of stage III and IV neuroblastoma: resection before or after chemotherapy?

Local control is vital for long-term survival for patients with stage III neuroblastoma, and although cure is difficult, ultimate success in stage IV neuroblastoma will necessitate control of the primary tumor as well as effective therapy of the metastases. The proper timing of surgical resection of the primary tumor is uncertain. Patients with stage III and IV neuroblastoma treated from 1977 to 1988 were retrospectively reviewed as to whether the resection was performed before or after chemotherapy. Complications assessed include significant blood loss, damage to adjacent organs, and delays before postsurgical chemotherapy could be given. Sixty patients were treated primarily at the authors' institution: 18 with stage III and 42 with stage IV disease. Chemotherapy consisted of combinations of nitrogen mustard, adriamycin, dacarbazine (DTIC), cisplatin, vincristine, and cyclophosphamide (MADDOC). Nine patients with stage III neuroblastoma underwent initial resection of the primary tumor before receiving chemotherapy. Three had complications, all with excessive blood loss (0.57, 2.0, and 3.0 times the estimated total blood volume [TBV]). One patient had renal infarction, and another had regrowth of the tumor before chemotherapy could be administered 35 days after surgery. There were no complications in the eight secondary explorations, four of which were complete resections. All had viable tumor in the resected specimen. Eleven of the 42 stage IV patients had primary resections, 5 of whom had complications: colocutaneous fistula, unilateral renal necrosis, chylothorax, and excessive blood loss (1.3 and 2 TBV). None of the 18 patients with delayed resection after 3 to 12 courses of chemotherapy had surgical complications with complete (14 patients), near complete (2 patients), or subtotal resections (2 patients).(ABSTRACT TRUNCATED AT 250 WORDS)

Aggressive surgery combined with intensive chemotherapy improves survival in poor-risk neuroblastoma

One hundred eighteen children with metastatic (Childrens Cancer Study Group [CCSG] stage IV), extensive regional (stage III), or stage II neuroblastoma with N-myc amplification received an intensive chemotherapeutic regimen of cis-platinum, etoposide, doxorubicin, and cyclophosphamide combined with persistent aggressive attempts at complete primary tumor resection. Fourteen patients were unevaluable and 42 left the study to be placed on bone marrow transplant protocols. The remaining 62 children were evaluated in detail. Complete excision was eventually accomplished in 39 patients (63%), 23 of whom are disease-free survivors after 8 to 47 months (median, 20 months). Twenty-three patients underwent partial excision or biopsy of their lesion and only 6 are alive without evidence of disease (P = .0011). Timing of surgery or site of tumor did not influence surgical outcome. N-myc oncogene expression could not predict which lesions would be completely resectable. Surgical complications occurred 21% of the time but the impact on the clinical course and chemotherapy administration was minimal. The ipsilateral kidney was removed with the tumor in 18 cases, 14 of which were during complete resection. Twelve of these children are disease-free survivors. With new intensive chemotherapy capable of eliciting an effective response from primary and metastatic neuroblastoma, aggressive surgical approaches for complete tumor resection are warranted and can be expected to improve patient outcome.

Morphological and cytogenetic characterization and N-myc oncogene analysis of a newly established neuroblastoma cell line

A permanent cell line established from a xenograft of neuroblastoma which occurred in a 5-year-old girl was investigated for its morphological and biological characteristics. The cultured cells were tumorigenic in nude mice. Microscopically, each tumor consisted of small round to polygonal cells with irregular nuclei and prominent nucleoli, corresponding to the features of the primary and xenografted tumor cells. Electron microscopic examination revealed that both the transplanted tumor cells and the cultured cells contained scanty microtubules and dense-core neurosecretory granules. Chromosome analysis of this cell line showed monosomy for chromosomes 1, 10, 19 and X, and structural rearrangements involving chromosomes 8, 17 and 20, in addition to numerous double minutes. The N-myc oncogene was found to be amplified 40- to 80-fold in the transplanted and cultured tumor cells, as well as in the primary tumor cells. In situ hybridization with a digoxigenin-labeled uridine-triphosphate N-myc RNA probe detected abundant mRNA in the tumor cells. This neuroblastoma line may become a valuable in vitro experimental model system for studies aimed at better characterization of neuroblastoma.

Expression of leucocyte adhesion molecules on 66 clinical neuroblastoma specimens

LFA-3, ICAM-1, HLA.ABC and HLA.DR expression was analyzed on 66 neuroblastoma specimens. HLA.ABC was expressed on 26 specimens, HLA.DR on 2, LFA-3 on 20 and ICAM-1 on 10. HLA.ABC and LFA-3 were positive on ganglioneuroblastoma or ganglioneuroma, but they were negative on neuroblastoma, independently of the clinical staging; HLA.ABC and LFA-3 were induced in vivo by chemotherapy in parallel with tumoral cell differentiation, in both the primary and the metastases. The expression of ICAM-1 was restricted to 5 of the 10 low-grade stage-1 or stage-2 specimens, 1 stage-3 specimen, and the primary tumors of 2 patients with stage-4 disease, analyzed hence at diagnosis and after chemotherapy (4 specimens); metastatic cells obtained in 1 of these patients were negative. HLA.ABC and LFA-3 expressed on both mycN-negative and -positive specimens, whereas ICAM-1 was restricted to MYCN-negative specimens. LFA-3 diffusely stained partially differentiated neuroblasts, Schwann cells and ganglion cells. The expression of HLA.ABC on differentiated neuroblasts varied from one sample to another and within the same tumor; Schwann cells were strongly positive, but ganglion cells were negative. In positive samples, ICAM-1 was expressed on differentiated neuroblasts and Schwann cells, but negative on ganglion cells; however, most of the differentiated tumors were ICAM-1-negative, suggesting ICAM-1 induction by unknown local signal. The 4 markers were negative on undifferentiated neuroblasts. The distribution of these 4 markers on clinical specimens was in agreement with their reactivity on fetal tissues, as well as with results obtained on neuroblastoma cell lines before and after in vitro treatment with IFN-gamma.

Polycythaemia and neuroblastoma

The treatment of primary proliferative polycythaemia (polycythaemia rubra vera) may include radioactive phosphorus (P32) in conjunction with venesection. Acute leukaemia or carcinoma can be associated with the use of P32. We present a case of primary proliferative polycythaemia treated by repeat venesection together with P32 whose follow-up was complicated by the development of malignant neuroblastoma.

Mass screening for neuroblastoma in Japan

The present status of the neuroblastoma mass screening program in Japan, the first national trial in the world, is evaluated. This program, now in its fifth year, was conducted in cooperation with the infants' mothers, local health centers, screening centers, and selected hospitals. From the onset of the program in Kyoto in 1973 to the end of 1989, 337 cases were detected and analyzed. Most cases were detected at early stages and 97% are expected to be cured. Several social, technical, and clinical problems remain unresolved.

Treatment of high-risk solid tumors of childhood with intensive therapy and autologous bone marrow transplantation

Autologous bone marrow transplantation (ABMT) allows delivery of intensive, marrow-ablative chemotherapy or chemoradiotherapy to children with high-risk solid tumors. Results from several studies of neuroblastoma suggest that outcome is improved by ABMT; however, relapses can occur months to years after complete clinical remission. Other high-risk tumors including peripheral neuroepithelioma, Ewing's sarcoma, rhabdomyosarcoma, Wilms' tumor, and brain tumors also appear to be responsive to intensive marrow-ablative therapy, although few studies have been reported. For tumors that can metastasize to marrow, a sensitive method is necessary for detecting tumor cell contamination. Immunocytologic analysis with monoclonal antibodies can identify one neuroblastoma cell per 10(5) normal marrow cells; this method also is applicable to other tumors with appropriate antibodies. Ex vivo removal (purging) of tumor cells decreases the probability of infusing tumorigenic cells with the ABMT. There is considerable experience in tumor detection and purging for neuroblastoma, but little has been done for other childhood solid tumors. Future investigations of ABMT will aim to further increase disease-free survival by intensifying induction and marrow-ablative regimens and by developing therapies to be given after ABMT that are directed at minimal residual disease. As pilot investigations mature, the efficacy of ABMT and conventional chemotherapy will be compared in multi-institution randomized studies.

Prognostic value of immunocytologic detection of bone marrow metastases in neuroblastoma

BACKGROUND

Morphologic evaluation of bone marrow for neuroblastoma cells is a routine and important component of clinical staging. Specific immunostaining of malignant cells with monoclonal antibodies should be more sensitive, however, and may improve the detection of metastases and provide additional prognostic information.

METHODS

We looked for tumor cells in bone marrow from 197 patients with newly diagnosed neuroblastoma, using immunoperoxidase staining with monoclonal antibodies (immunocytologic analysis) and examination of smears and specimens obtained by trephine biopsy (conventional analysis).

RESULTS

Routine smears and trephine-biopsy specimens were positive for tumor cells in 46 percent of the patients, whereas 67 percent were positive on immunocytologic analysis (P less than 0.0001). Immunocytologic analysis detected bone marrow metastases in 34 percent of patients considered to have only localized or regional disease (Stage I, II, or III). It also identified tumor cells that were not detected by conventional analysis in patients with widespread disease (Stage IV or IVS). Tumor content, as determined by immunocytologic analysis, predicted clinical outcome in relation to the age of the patient at diagnosis. Patients with Stage II or III disease diagnosed after one year of age who did not have occult marrow metastases did well, whereas those with metastases did poorly (P = 0.006). Patients in whom Stage IV disease was diagnosed before they were one year of age did well if bone marrow metastases were few or absent, but had poor survival if the marrow contained more than 0.02 percent tumor cells (P = 0.03).

CONCLUSIONS

Immunocytologic analysis of bone marrow aspirates is more sensitive than conventional analysis in detecting tumor cells and provides prognostic information. The relations among marrow metastases, age at diagnosis, and clinical outcome illustrate the biologic heterogeneity of neuroblastoma.

Fluctuation in the concentrations of vanillylmandelic acid and homovanillic acid in mass screening for neuroblastoma

Fluctuations in the amount of vanillylmandelic acid (VMA) and homovanillic acid (HVA) were studied in random urine samples from 13 infants with neuroblastoma. In patients with a small tumour, many samples contained amounts below the cut off values, suggesting that detection of a patient with neuroblastoma depended on mathematical probability. Using high performance liquid chromatography a patient with a tumour of about 10 g may well be overlooked, whereas a patient whose tumour weighs over 30 g would probably be detected. With qualitative screening, although more likely to miss a patient with low VMA excretion, a patient with a tumour weighing over 50 g would be detected. In a thorough hospital examination care should be exercised in interpreting borderline values of VMA and HVA; excretion information suggesting the existence of a tumour may aid localization by radiological imaging procedures.

N-myc oncogene expression and amplification in metastatic lesions of stage IV-S neuroblastoma

The authors determined the levels of N-myc oncogene amplification and RNA expression in three infants with metastatic neuroblastoma. By clinical staging Patients 1 and 2 were Stage IV-S, a disease with limited metastatic potential and generally favorable outcome; Patient 3 was Stage IV. Southern blots of chromosomal DNA showed normal N-myc copy number in the primary tumor of Patient 1, extensive (200-fold) gene amplification in the primary tumor from Patient 2, and intermediate (100-fold) gene amplification in the primary tumor and metastatic lesions from Patient 3. N-myc RNA was expressed in all of the primary and metastatic tumor tissues tested. The level of N-myc RNA expression roughly corresponded to the extent of N-myc gene amplification in Patients 2 and 3 and was overexpressed from a single N-myc gene copy in Patient 1. N-myc gene amplification and RNA expression levels were approximately the same in the primary and metastatic lesions for each of the patients tested. The two patients with N-myc gene amplification had a poor outcome, but the patient with normal N-myc gene copy number had no evidence of disease. Despite the clinical picture in Patient 2 of Stage IV-S neuroblastoma, the pattern of N-myc amplification and expression more closely resembled that of Patient 3 (Stage IV neuroblastoma) than that of Patient 1 (bona fide Stage IV-S neuroblastoma).

A case of cerebral composite ganglioneuroblastoma: an immunohistochemical and ultrastructural study

An unusual cerebral tumor is reported in a 14-year-old boy. On light and electron microscopy, the constituent cells were very complex; the majority of the neoplastic cells were primitive neuroectodermal cells dispersed in myxomatous or fibrous stroma. Neoplastic neuronal cells and hypertrophic astrocytes were also observed in these areas. The neuronal cells showed a continuous spectrum of differentiation from very primitive to mature ganglion cells. Furthermore, the tumor contained a highly cellular discrete area consisting of neuroblasts and their precursor cells. From these findings, a diagnosis of composite ganglioneuroblastoma was made.

Chromogranin A in children with neuroblastoma. Serum concentration parallels disease stage and predicts survival

Chromogranin A is an acidic protein costored and coreleased with catecholamines from storage vesicles. Its serum concentration is elevated in patients with peptide-producing endocrine neoplasia. We measured serum chromogranin A at the time of diagnosis in 34 children with all stages of neuroblastoma. With a sensitivity of 91% and specificity of 100%, serum chromogranin A emerged as a useful diagnostic tool for neuroblastoma, comparable to or better than other measurements such as neuron-specific enolase, ferritin, or dopamine-beta-hydroxylase. Mean serum chromogranin A correlated with disease stage (r = 0.76, P less than 0.01). The relationship of prognosis (progression-free survival) to baseline serum chromogranin A, age, and disease stage was determined in 34 patients at risk for relapse, with a median followup period of 18 mo (range, 1-48 mo). The survival rate for patients with lower serum chromogranin A levels (less than 190 ng/ml at the time of diagnosis) was 69%, whereas it was 30% for those with higher chromogranin A levels (P less than 0.05). Furthermore, when subjects were additionally stratified by either age or stage, chromogranin A was an effective prognostic tool in patients who either were older than 1 yr (P less than 0.005) or had more advanced disease (stage III or IV; P less than 0.05). We conclude that serum chromogranin A in neuroblastoma is (a) a valuable (sensitive and specific) diagnostic tool, (b) a correlate of tumor burden, and (c) a useful predictor of survival.

Neuroblastoma in a child with Wiedemann-Beckwith syndrome

We report on a patient with Wiedemann-Beckwith syndrome (WBS) who developed abdominal neuroblastoma. Although WBS patients are known to have a higher incidence of embryonal tumors, this is only the 4th known case of neuroblastoma associated with this syndrome. Chromosomes on peripheral lymphocytes and tumor cells were normal. Children with WBS should be screened for a variety of embryonal neoplasms, not only Wilms tumor.

Advances and management of solid tumors in children

In recent years there has been a significant improvement in the survival rate of children with malignant solid tumors. With Wilms' tumor, the survival rate has risen to 80%, but a subset of these patients with unfavorable histologies and therefore a higher rate of relapse need a different strategy. For those patients with soft tissue sarcoma, brain tumors, and bone tumors the combination of preoperative chemotherapy, surgery, and radiotherapy followed by maintenance multiagent chemotherapy has resulted in a survival rate of 45% to 70%. In the case of neuroblastoma, a similar aggressive approach has not resulted in an improved survival. A different approach that uses screening of infants by urinary testing for VMA and HVA to detect earlier and potentially less malignant tumors has begun in Japan and North America in the hope that preclinical detection will reduce mortality.

Improvement in prognosis of neuroblastoma through mass population screening

Since April 1981, the city of Sapporo, Japan, has conducted a mass screening program to measure urinary vanillylmandelic acid and homovanillylic acid using high-performance liquid chromatography. This program was expanded to the entire island of Hokkaido in October 1987. Mass screening proved beneficial, resulting in an increase in patients diagnosed with neuroblastoma under 1 year of age from 17% to 66%, an increase in stage I cases from 9% to 26%, an increase in stage III cases from 9% to 32%, and an increase in the tumor resectability rate from 15.1% to 58%. These improvements raised the 5-year survival rate for neuroblastoma from 23% to 66.7%. An additional study of these mass screening cases using Shimada's classification showed a wide range of histopathological distribution, and it demonstrated the usefulness of such a program in identifying the tumors most in need of early treatment.

Histopathologic features of composite ganglioneuroblastoma. Immunohistochemical distinction of the stromal component is related to prognosis

Histopathologic features of 18 cases of composite ganglioneuroblastoma (CGNB) were studied with immunohistochemical staining techniques using antibodies against S-100 protein (S-100), ferritin (FER), and leukocytic common antigen (LCA). Cases of CGNB were divided on the basis of the morphologic features of neuroblastic elements into three prognostic subgroups: "Type A Intermixed," having individual microscopic nests of neuroblasts (N = 4, 100% survival); "Type B Intermixed," having microscopic aggregates of multiple neuroblastic nests (N = 6, 67% survival); and "Nodular," having grossly visible nodule(s) of neuroblastic proliferation (N = 8, 0% survival). Survival rates are significantly different for the prognostic subgroups (P less than 0.025). Each prognostic subgroup demonstrated an immunohistochemically distinct pattern of stromal cell composition in the neuroblastic elements: Type A Intermixed had numerous S-100 cells and no FER cells, Type B Intermixed contained many S-100 cells and a moderate number of FER cells, and Nodular had few S-100 cells with many FER cells. The S-100 and FER scores, determined by counting the positive cells through a line sampling method, differed significantly between these prognostic subgroups. Lymphocytic aggregations in tumor tissue evaluated by volumetric assessment with LCA staining, on the other hand, showed no contribution in predicting the outcome of the patients. There was also an inverse relationship between S-100 and FER score, suggesting a relationship between the relative predominance of these stromal cell types, tumor histopathologic features, and the biologic behavior of CGNB.

Neuroblastoma and other childhood neural tumors: a review

Neuroblastoma is the most common nonhematopoietic solid tumor of childhood and has been intensively studied for at least 4 decades. Despite this, few predictive histopathologic clues to its behavior exist. Age, anatomic sites of occurrence, and clinical stage have traditionally been the only reliable prognostic factors in this disease. A number of laboratory studies that focus on biologic features such as neurotransmitter synthesis (adrenergic and noradrenergic catecholamines), neurotransmitter enzyme expression (dopamine beta hydroxylase, choline acetyl transferase), cytogenetics (homogeneously staining regions, double minute chromosomes, chromosome 1p deletions), molecular genetics (N-myc oncogene amplification and expression), and immunophenotype (surface epitopes such as HLA antigens and GD2 ganglioside and intracytoplasmic determinants such as neurofilament protein, synaptophysin, chromogranin, and neuron specific enolase) now enable the pathologist to predict clinical course in many cases and to distinguish bona fide neuroblastomas, regardless of age, site, or histologic appearance, from a host of related but distinctly separate neuroectodermal tumor entities with apparent different histogenesis, treatment sensitivity, and prognosis.

An assessment of volume-weighted mean nuclear volume estimates as a prognostic index for neuroblastoma

This study evaluates an objective, unbiased, stereologic parameter (volume-weighted mean nuclear volume vV) as a prognostic indicator for survival of neuroblastoma in comparison with three histopathologic grading systems. In this retrospective study 24 consecutive, nonselected patients from the registry of Royal Liverpool Children's Hospital, Alder Hey, England were analyzed. Only primary lesions obtained before chemotherapy were used. Follow-up time in surviving patients (n = 10) was 4.5 to 20 years. All lesions were regraded blind and twice by two pathologists. vV was estimated on routinely processed, hematoxylin and eosin-stained, 5-microns sections, requiring on average less than 20 min per patient. Results show an absolute cut-off point for survival at vV = 270 microns 3. No patient with vV less than this value is alive at present (n = 7). In addition, actuarial survival curves for nonsurvivors show a bimodal pattern of survival time, separating patients with vV greater than (n = 7) and less than (n = 7) 270 microns 3. In comparison with the same analysis for the results of regrading by means of the Hughes or Beckwith system, results of vV estimation were superior. In comparison with the Shimada system the results confirmed the strong dichotomy for survivors and nonsurvivors, although with more overlap. vV has the advantage of predicting length of survival in nonsurvivors. The combination of Shimada grading and vV measurement, on the basis of the material studied, seems to offer useful prediction of biologic behavior. vV was always estimated on the small cell population, reducing the problems of biopsy representability.

Neuroblastoma and DiGeorge anomaly

DiGeorge anomaly is a rare disorder felt to be a complex neurocristopathy. We report the unusual association of congenital neuroblastoma arising in an infant with the DiGeorge anomaly.

Expression of a drug resistance gene in human neuroblastoma cell lines: modulation by retinoic acid-induced differentiation

Expression of a multidrug resistance gene (mdr1) and its protein product, P-glycoprotein (Pgp), has been correlated with the onset of multidrug resistance in vitro in human cell lines selected for resistance to chemotherapeutic agents derived from natural products. Expression of this gene has also been observed in normal tissues and human tumors, including neuroblastoma. We therefore examined total RNA prepared from human neuroblastoma cell lines before and after differentiation with retinoic acid or sodium butyrate. An increase in the level of mdr1 mRNA was observed after retinoic acid treatment of four neuroblastoma cell lines, including the SK-N-SH cell line. Western blot (immunoblot) analysis demonstrated concomitant increases in Pgp. However, studies of 3H-vinblastine uptake failed to show a concomitant Pgp-mediated decrease in cytotoxic drug accumulation. To provide evidence that Pgp was localized on the cell surface, an immunotoxin conjugate directed against Pgp was added to cells before and after treatment with retinoic acid. Incorporation of [3H]leucine was decreased by the immunotoxin in the retinoic acid-treated cells compared with the undifferentiated cells. These results demonstrate that whereas expression of the mdr1 gene can be modulated by differentiating agents, increased levels of expression are not necessarily associated with increased cytotoxic drug accumulation.

Clinical value of N-myc oncogene amplification in 52 patients with neuroblastoma included in recent therapeutic protocols

Southern blot analysis of neuroblastoma (NB) cell DNA from 52 patients (58 samples) allowed the detection of an N-myc amplification on three of the 13 BM samples and three of 13 tumor samples at diagnosis, on two of 17 tumor samples taken after induction therapy, on three of seven BM samples and two of the five local tumor samples taken after relapse. N-myc was amplified in two of the 15 patients with stage I to III NB and in 10 of the 36 patients with stage IV neuroblastoma over 1 year of age. Conclusions from the analysis are as follows: first tumor samples obtained on previously treated patients are histologically modified and detection of N-myc amplification is not accurate; consequently N-myc amplification must be defined at diagnosis. Surgical biopsies of the primary tumors can, however, be delayed and malignant cells obtained by ultrasound-guided punctures or analyzed on bone marrow samples if they represent more than 50% of the total population. Second, any attempt to define the prognostic value must be performed on a group of patients treated with a new aggressive protocol of chemotherapy; it will require a multiparametric analysis including, in particular, results of an extensive clinical staging at diagnosis and histological criteria.

Expression of a drug resistance gene in human neuroblastoma cell lines: modulation by retinoic acid-induced differentiation

Expression of a multidrug resistance gene (mdr1) and its protein product, P-glycoprotein (Pgp), has been correlated with the onset of multidrug resistance in vitro in human cell lines selected for resistance to chemotherapeutic agents derived from natural products. Expression of this gene has also been observed in normal tissues and human tumors, including neuroblastoma. We therefore examined total RNA prepared from human neuroblastoma cell lines before and after differentiation with retinoic acid or sodium butyrate. An increase in the level of mdr1 mRNA was observed after retinoic acid treatment of four neuroblastoma cell lines, including the SK-N-SH cell line. Western blot (immunoblot) analysis demonstrated concomitant increases in Pgp. However, studies of 3H-vinblastine uptake failed to show a concomitant Pgp-mediated decrease in cytotoxic drug accumulation. To provide evidence that Pgp was localized on the cell surface, an immunotoxin conjugate directed against Pgp was added to cells before and after treatment with retinoic acid. Incorporation of [3H]leucine was decreased by the immunotoxin in the retinoic acid-treated cells compared with the undifferentiated cells. These results demonstrate that whereas expression of the mdr1 gene can be modulated by differentiating agents, increased levels of expression are not necessarily associated with increased cytotoxic drug accumulation.

Neuroblastoma in an adult causing spinal cord compression: report of a case and review of the literature

Adult neuroblastoma (ANB) is an uncommon malignancy, there being only 42 reported cases in the world literature. The purpose of this report is to present a case of ANB with spinal cord compression by an intraspinal component, and review methods of diagnosis and treatment. NB is one of the most frequent childhood malignancies (90% of the patients are less than 10 years old) and both pathologists and clinicians tend to exclude it from differential diagnosis when the patient is an adult. When the tumour is located in the paraspinal region, local extension through the intervertebral foramen into the spinal canal can occur in a dumbbell fashion, a pattern of growth first described by Weber in 1856.

Advanced neuroblastoma: results of two treatment programs including sequential hemibody irradiation

Results of two consecutive treatment programs for advanced neuroblastoma, including sequential hemibody irradiation, are analyzed and compared. The first treatment program (I-TP) included one single-fraction (7 Gy) irradiation to the upper and lower halves of the body as consolidation of remission achieved by previous chemotherapy with CDDP and VP16. A fractionated technique (2 Gy daily for 4 consecutive days to each hemibody) was used in the second treatment program (II-TP) for children in remission following a combination of CDDP + VP16 and ADM + VCR + CTX. In both treatment programs, chemotherapy was continued according to the same pre-radiation regimen following the two sessions of hemibody irradiation. Overall response rate to pre-radiation chemotherapy was 84% and 60% for I-TP and II-TP, respectively. Thirty-month overall progression-free survival was 0 for I-TP and 20% for II-TP. No treatment-related fatalities occurred. In the subsets of patients who reached complete or good partial remission during the pre-radiation chemotherapeutic phase, 30-month progression-free survival in I-TP and II-TP was 0 and 33%, respectively. The role of fractionated hemibody irradiation in prolonging the progression-free survival can be inferred.

Abdominal, retroperitoneal and sacrococcygeal tumours of the newborn and the very young infant. Report from the Kiel Paediatric Tumour Registry

We examined 226 abdominal, retroperitoneal and sacrococcygeal tumours in newborns and infants aged 6 months or less. Most frequent were neuroblastomas (n = 83) followed by germ cell tumours (n = 76), 37 of which were immature and 32 were mature teratomas. Fully malignant germ cell tumours and malignant germ cell tumour components were much rarer in this age group (9.2%) than in older children (58.1%). The majority of germ cell tumours were localized in the sacrococcygeal region (72.4%). Next in frequency were tumours of the kidney (n = 54), including 28 congenital mesoblastic nephromas. In contrast to children over 6 months of age, kidney tumours were frequently low grade malignant with a favourable prognosis. Among liver tumours there were 19 infantile haemangioendotheliomas and 9 hepatoblastomas. By contrast, at ages 7-24 months hepatoblastomas (n = 28) were much more frequent than haemangioendotheliomas (n = 2). Tumours in the newborn and very young infant differ from those in older children in many respects: (1) the relative frequency; (2) localization; (3) distribution of histological types; (4) degree of differentiation, often associated with a tendency toward maturation but occasionally also with increasing malignancy; and (5) prognosis, which is comparatively favourable.

Accuracy of diagnostic imaging as determined by delayed operative intervention for advanced neuroblastoma

Current treatment of newly diagnosed widespread neuroblastoma may include chemotherapy, delayed surgical resection, marrow ablative chemoradiotherapy, and bone marrow transplantation. Diagnostic imaging (DI) with computerized tomography (CT) or magnetic resonance imaging (MRI) has been used to determine response to therapy and timing of delayed resection. We assessed the accuracy of DI in 25 patients (26 total cases) treated over 21 months. Tumor size and location were estimated prior to surgical resection by DI, and the sensitivity and specificity of these studies were determined from operative findings. DI consisted of CT (15), MRI (8), and MRI and CT (3). Discordance between DI and operative findings was found in ten patients (38%). This included three errors of sensitivity (12%), including two false-positives and one false-negative. Seven errors of specificity were noted; they included a positive scan with no viable tumor identified (3), much more extensive disease (3), or less extensive disease (1). Viable tumor was identified in 18 cases, and in 11 patients, complete resection of macroscopic tumor at the primary site was carried out. Ten of 13 patients operated on within 5 months of beginning chemotherapy were rendered grossly free of neuroblastoma at the primary site after surgery. Eight of 12 patients operated on 6 months or longer after starting chemotherapy were rendered grossly free of tumor at the primary site. Bone marrow transplantation was performed in 21 patients, ten of whom are alive with a median follow up of 20 months. Survival was similar for patients who underwent surgical resection at less than or equal to 5 v greater than 6 months after starting chemotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)

A surgical perspective on the current staging in neuroblastoma--the International Neuroblastoma Staging System proposal

In the three most widely used neuroblastoma staging systems--Evans, Pediatric Oncology Group (POG), and TNM-Union Internationale Contre le Cancer (UICC)--few staging problems are presented by the completely resected tumor or with the patient who has metastatic disease. Difficulties arise with the localized tumor when there is extension across the midline and with the demonstration of lymph node involvement. A new International Staging System for Neuroblastoma (INSS) is proposed that incorporates both lymph node invasion and extension across the midline into surgical staging. Clear criteria for diagnosis are established and clinical responses are defined. New prognostic factors may be added. The surgical role remains significant in staging, diagnosis, and therapy. Use of a common system throughout the world would facilitate the evaluation of clinical trials and help achieve the goal of developing optimum therapy for the biologically different types of neuroblastoma.

Differential expression of N-myc and c-src proto-oncogenes during neuronal and schwannian differentiation of human neuroblastoma cells

Neuroblastoma (NB) cells can be induced to differentiate bidirectionally into either neuronal or schwannian cells by different inducers. However, the underlying mechanisms are poorly understood. We examined the expression of N-myc and c-src genes in 3 human NB-cell lines during either neuronal or schwannian differentiation in vitro, since proto-oncogenes are considered to play a pivotal role in regulating cell proliferation and differentiation. Decreased N-myc expression and increased c-src expression were observed during neuronal differentiation by retinoic acid, polyprenoic acid (E5166) and dibutyryl cyclic AMP, whereas the expression of N-myc and c-src genes was considerably reduced during schwannian differentiation by bromodeoxyuridine, demonstrating that the expression of N-myc and c-src genes was regulated independently in the bipolar differentiation processes of NB cells. Our results suggest that enhanced N-myc expression might be closely linked to the undifferentiated phenotypes of NB cells, that c-src expression might be related to the neuronal differentiation of NB cells, and that N-myc and c-src genes might be regulated independently in the determination of the bipolar differentiation of NB cells.