Flow cytometric DNA analysis of neuroblastoma and ganglioneuroma. A 10-year retrospective study

Health Insurance Coverage and Racial/Ethnic Disparities in U.S. Childhood and Adolescent Cancer Survival

OBJECTIVE

To evaluate potential effect modification by health insurance coverage on racial and ethnic disparities in cancer survival among U.S. children and adolescents.

STUDY DESIGN

Data from 54,558 individuals diagnosed with cancer at ≤ 19 years between 2004 and 2010 were obtained from the National Cancer Database. Cox proportional hazards regression was used for analyses. An interaction term between race/ethnicity and health insurance type was included to examine racial/ethnic disparities in survival by each insurance status category.

RESULTS

Racial/ethnic minorities experienced a 14-42% higher hazard of death compared with non-Hispanic Whites with magnitudes varying by health insurance type (P_interaction < 0.001). Specifically, among those reported as privately insured, the hazard of death was higher for non-Hispanic Blacks (hazard ratio [HR]=1.48, 95% confidence interval [CI]: 1.36-1.62), non-Hispanic American Indian/Alaskan Natives (HR=1.30, 95%CI: 1.13-1.50), non-Hispanic Asians or Pacific Islanders (HR=1.99, 95%CI: 1.36-2.90) and Hispanics (HR=1.28, 95%CI: 1.17-1.40) vs. non-Hispanic Whites. Racial/ethnic disparities in survival among those reported as covered by Medicaid were present for non-Hispanic Blacks (HR=1.30, 95%CI: 1.19-1.43) but no other racial/ethnic minorities (HR ranges: 0.98∼1.00) vs. non-Hispanic Whites. In the uninsured group, the hazard of death for non-Hispanic Blacks (HR=1.68, 95%CI: 1.26-2.23) and Hispanics (HR=1.27, 95%CI: 1.01-1.61) was higher vs. non-Hispanic Whites.

CONCLUSIONS

Disparities in survival exist across insurance types, particularly for non-Hispanic Black childhood and adolescent cancer patients vs. non-Hispanic Whites with private insurance. These findings provide insights for research and policy and point to the need for more efforts on promoting health equity while improving health insurance coverage.

Racial and ethnic disparities in risk and survival in children with neuroblastoma: a Children's Oncology Group study

PURPOSE

Although health disparities are well-described for many cancers, little is known about racial and ethnic disparities in neuroblastoma. To evaluate differences in disease presentation and survival by race and ethnicity, data from the Children's Oncology Group (COG) were analyzed.

PATIENTS AND METHODS

The racial/ethnic differences in clinical and biologic risk factors, and outcome of patients with neuroblastoma enrolled on COG ANBL00B1 between 2001 and 2009 were investigated.

RESULTS

A total of 3,539 patients (white, 72%; black, 12%; Hispanic, 12%; Asian, 4%; and Native American, < 1%) with neuroblastoma were included. The 5-year event-free survival (EFS) rates were 67% for whites (95% CI, 65% to 69%), 69% for Hispanics (95% CI, 63% to 74%), 62% for Asians (95% CI, 51% to 71%), 56% for blacks (95% CI, 50% to 62%), and 37% for Native American (95% CI, 17% to 58%). Blacks (P < .001) and Native Americans (P = .04) had a higher prevalence of high-risk disease than whites, and significantly worse EFS (P = .01 and P = .002, respectively). Adjustment for risk group abrogated these differences. However, closer examination of the EFS among high-risk patients who remained event free for 2 years or longer, revealed a higher prevalence of late-occurring events among blacks compared with whites (hazard ratio, 1.5; 95% CI, 1.0 to 2.3; P = .04).

CONCLUSION

Black and Native American patients with neuroblastoma have a higher prevalence of high-risk disease, accounting for their worse EFS when compared with whites. The higher prevalence of late-occurring events among blacks with high-risk disease suggests that this population may be more resistant to chemotherapy. Studies focused on delineating the genetic basis for the racial disparities observed in this study are planned.

A model for genetic complementation controlling the chromosomal abnormalities and loss of heterozygosity formation in cancer

The relationship between the apparently random chromosomal changes found in aneuploidy and the genetic instability driving the progression of cancer is not clear. We report a test of the hypothesis that aneuploid chromosomal abnormalities might be selected to preserve cell-survival genes during loss of heterozygosity (LOH) formations which eliminate tumor suppressor genes. The LOHs and structurally abnormal chromosomes present in the aneuploid LoVo (colon), A549 (lung), SUIT-2 (pancreas), and LN-18 (glioma) cancer cell lines were identified by single nucleotide polymorphisms (SNPs) and Spectral Karyotyping (SKY). The Mann-Whitney U and chi square tests were used to evaluate possible differences in chromosome numbers and abnormalities between the cell lines, with two-tailed P values of <0.01 being considered significant. The cell lines differed significantly in chromosome numbers and frequency of structurally abnormal chromosomes. The SNP analysis revealed that each cell line contained at least a haploid set of somatic chromosomes, consistent with our hypothesis that cell-survival genes are widely scattered throughout the genome. Further, over 90% of the chromosomal abnormalities seemed to be selected, often after LOH formation, for gene-dosage compensation or to provide heterozygosity for specific chromosomal regions. These results suggest that the chromosomal changes of aneuploidy are not random, but may be selected to provide gene-dosage compensation and/or retain functional alleles of cell-survival genes during LOH formation.

Comprehensive analysis of tumoral DNA content reveals clonal ploidy heterogeneity as a marker with prognostic significance in locoregional neuroblastoma

The clinical management of locoregional neuroblastoma (LR NB) is controversial. In a previous study we showed that diploidy was a strong prognostic predictor of outcome and detected the existence of clonal ploidy heterogeneity in a select group of cases. The aims of this study were (1) to assess the frequency of ploidy heterogeneity in LR NB, (2) to ascertain the best method to detect heteterogeneity, and (3) to correlate ploidy populations with clinical outcome. We undertook a comprehensive analysis of tumoral DNA content in 38 LR NBs comparing (1) flow cytometry (FCM), (2) karyotyping, (3) interphase fluorescence in situ hybridization, and (4) laser-scanning cytometry (LSC). Tumor ploidy heterogeneity was found by all methodologies. By FCM, all tumors with aneuploid peaks had detectable diploid DNA peaks. By LSC, all tumors with diploid and hyperploid peaks were GD2-positive in both, consistent with their tumoral origin. A predominant near-triploid clonal population (ratio diploid vs. triploid, <2.5) was observed in most nonprogressing LR NB tumors, and a predominant diploid clone (ratio di- vs. triploid, >2.5) in most progressing LR NB cases. Multivariate analysis was performed to evaluate the prognostic value of tumor ploidy assayed by different methods versus age, INSS (International Neuroblastoma Staging System) stage, and MYCN status. FCM was the most powerful prognostic factor related to poor prognosis (overall survival, P = 0.02; progression-free survival, P = 0.01). These results provide strong evidence for clonal ploidy heterogeneity in LR NB and clonal evolution toward diploidy in progressing LR NB.

Improving morphology-based malignancy grading schemes in astrocytic tumors by means of computer-assisted techniques

We propose an original methodology which improves the accuracy of the prognostic values associated with conventional morphologically-based classifications in supratentorial astrocytic tumors in the adult. This methodology may well help neuropathologists, who must determine the aggressiveness of astrocytic tumors on the basis of morphological criteria. The proposed methodology comprises two distinct steps, i.e. i) the production of descriptive quantitative variables (related to DNA ploidy level and morphonuclear aspects) by means of computer-assisted microscopy and ii) data analysis based on an artificial intelligence-related method, i.e. the decision tree approach. Three prognostic problems were considered on a series of 250 astrocytic tumors including 39 astrocytomas (AST), 47 anaplastic astrocytomas (ANA) and 164 glioblastomas (GBM) identified in accordance with the WHO classification. These three problems concern i) variations in the aggressiveness level of the high-grade tumors (ANA and GBM), ii) the detection of the aggressive as opposed to the less aggressive low-grade astrocytomas (AST), and iii) the detection of the aggressive as opposed to the less aggressive anaplastic astrocytomas (ANA). Our results show that the proposed computer-aided methodology improves conventional prognosis based on conventional morphologically-based classifications. In particular, this methodology enables some reference points to be established on the biological continuum according to the sequence AST-->ANA-->GBM.

Clinical significance of a highly sensitive analysis for gene dosage and the expression level of MYCN in neuroblastoma

BACKGROUND

The amplification of the MYCN gene is one of the most powerful adverse prognosis factors in neuroblastoma, but the clinical significance of an enhanced expression of MYCN remains controversial. To reassess the clinical implications of MYCN amplification and expression in neuroblastoma, the status of amplification and the expression level of the MYCN gene of primary neuroblastoma samples were analyzed using highly sensitive analyses.

METHODS

Using a quantitative polymerase chain reaction (PCR) method (TaqMan), the gene dosages (MYCN/p53) of 66 primary neuroblastoma samples were determined. In all 66 samples, the status of MYCN amplification has been determined previously by the Southern blotting method. Of the 54 samples with a single copy of MYCN based on the Southern blotting method, 23 samples were analyzed for MYCN amplification using the fluorescence in situ hybridization (FISH) method. The expression levels (MYCN/GAPDH) of 56 samples were determined by a quantitative reverse transcriptase (RT)-PCR method.

RESULTS

Of the 54 samples with a single copy of MYCN based on the Southern blotting method, 46 samples showed MYCN gene dosages of less than 2.0, whereas the remaining 8 samples with dosages of more than 2.0 were tumors from patients with advanced-stage disease. The results of FISH supported the fact that these 8 samples contained a small number of MYCN-amplified cells. The cases of MYCN gene dosages of more than 2.0 were significantly associated with all other unfavorable prognostic factors (an age of >1 year at diagnosis [P <.0001], nonmass screening [P =.0003], advanced stage [P <.0001], diploid or tetraploid [P <.0001], and a Shimada unfavorable histology [P <.0001]). MYCN gene dosages of more than 2.0 were significantly associated with a high expression of MYCN (P =.0459). However, the expression level of MYCN was not significantly associated with any other prognostic factors.

CONCLUSIONS

Quantitative PCR may thus be a useful modality for performing a highly sensitive and accurate assessment of the amplification and expression levels of the MYCN gene. In particular, the combination of the quantitative PCR system and the FISH method is considered to be a highly effective method for evaluating the status of MYCN amplification. In this highly sensitive analysis, MYCN amplification (MYCN/p53 > or = 2.0) was reconfirmed to be a strongly unfavorable factor, whereas the expression level of MYCN does not appear to be an independently significant prognosis factor.

Chromosomal variations within aneuploid cancer lines

Aneuploid cancers exhibit a wide spectrum of clinical aggressiveness, possibly because of varying chromosome compositions. To test this, karyotypes from the diploid CCD-34Lu fibroblast and the aneuploid A549 and SUIT-2 cancer lines underwent fluorescence in situ hybridization (FISH) and DAPI counterstaining. The number of DAPI-stained and FISH-identified chromosomes, 1-22, X,Y, as well as structural abnormalities, were counted and compared using the chi(2), Mann-Whitney rank sum test and the Levene's equality of variance. Virtually all of the evaluable diploid CCD-34Lu karyotypes had 46 chromosomes with two normal-appearing homologues. The aneuploid chromosome numbers per karyotype were highly variable, averaging 62 and 72 for the A549 and SUIT-2 lines, respectively. However, the A549 chromosome numbers were more narrowly distributed than the SUIT-2 karyotype chromosome numbers. Furthermore, 25% of the A549 chromosomes had structural abnormalities compared to only 7% of the SUIT-2 chromosomes. The chromosomal compositions of the aneuploid A549 and SUIT-2 cancer lines are widely divergent, suggesting that diverse genetic alterations, rather than chance, may govern the chromosome makeups of aneuploid cancers.

Evaluation of genetic heterogeneity in neuroblastoma

BACKGROUND AND METHODS

The prognosis in neuroblastoma, which is the most common solid tumor in children, tends to vary greatly, and many studies have demonstrated both clinical and biological factors to be closely correlated with the outcome. In order to select the optimal treatment according to the degree of malignancy of neuroblastoma, it is essential to accurately and rapidly identify any genetic heterogeneity associated with the prognosis. We assessed the status of some genetic abnormalities (MYCN amplification, deletion of the short arm of chromosome 1, DNA ploidy, and a gain of the chromosome 17q region) associated with the prognosis using several molecular biological methods.

RESULTS AND CONCLUSIONS

The combination of several molecular biological techniques is thus considered to be useful for elucidating the degree of malignancy of neuroblastoma. In particular, diagnostic analyses based on a combination of the fluorescence in situ hybridization (FISH) method and the quantitative polymerase chain reaction (PCR) method may be considered to be the most effective methods for quickly and accurately evaluating any aberrations in the gene dosages associated with the patients' outcomes.

Clinical and biologic characteristics for recurring neuroblastoma at mass screening cases in Japan

BACKGROUND

It is said that most cases detected by neuroblastoma mass screening at 6 months of age tend to have a favorable clinical course after a surgical resection either with or without mild chemotherapy. However, a few cases have an unfavorable outcome. In the current study, the authors analyzed the clinical and biologic characteristics for recurring neuroblastoma in mass screening cases.

METHODS

In 245 cases detected through mass screening in the Kyushu area in Japan, the clinical data and biologic features (N-myc status, DNA ploidy, Shimada histology, neuron-specific enolase (NSE), ferritin) were investigated, whereas, in particular, the data for recurring cases also were analyzed.

RESULTS

Of 245 cases, 28 tumors had one or more biologically unfavorable prognostic factors, and 6 patients experienced recurrence. Three of the six patients with recurring disease underwent a complete resection of the primary tumor, whereas three cases had undergone an incomplete resection of the tumor. Regarding the initial chemotherapy, three cases received mild chemotherapy, two cases received no chemotherapy, and one case had high-dose multidrug chemotherapy. Regarding biologic prognostic factors, four of six cases with recurring disease had one or more unfavorable factors, whereas two cases had no unfavorable factors. Regarding the outcome after recurrence, four cases are CR, one case has a stable residual tumor, and one case died of disease with N-myc amplification.

CONCLUSIONS

Most neuroblastomas detected by mass screening at 6 months of age have biologically favorable factors. However, approximately 10% of the cases had one or more unfavorable factors and thus might have a higher risk of recurrence than the patients with no unfavorable factors. Conversely, some cases with recurring disease had no unfavorable factors; however, the reason for this is still unclear. A long-term follow-up for mass screening cases is important, and it also might be necessary to research the established biologic factors and identify other new prognostic factors.

Genetic heterogeneity and clonal evolution in neuroblastoma

Tumour heterogeneity and clonal evolution at the genetic level may explain the development of malignant or resistant disease during clinical progression of neuroblastoma (NB). In this report we use 1p allelic analysis and DNA ploidy to evaluate clonal heterogeneity and clonal selection in vivo. We studied a total of 69 tumours from 29 patients with NB. To evaluate tumour heterogeneity and clonal evolution in vivo we used a panel of polymorphic allelic markers mapping to chromosome 1. 33 tumours from 12 patients (group 1) were obtained from different sites during the same surgery or at sequential surgeries without intervening chemotherapy to evaluate genetic heterogeneity. Paired samples from 10 patients (group 2) were used to evaluate clonal selection before and after chemotherapy. In 6 cases paired tumours and derived cell lines were studied. Analysis of DNA ploidy changes by karyotype, FISH and flow cytometry was performed in 15 tumours from 6 multiply recurred local-regional (LR) NB patients. Allelotype study revealed that 66% (8/12) of group 1 samples were heterogeneous, with distinct allelic patterns in tumour samples separated by time or location. In group 2 allelic patterns were different in post-chemotherapy specimens in 60% (6/10). DNA ploidy analysis showed that pre-chemotherapy samples contained 2 distinct ploidy clones, one diploid and one triploid, whereas all post-chemotherapy tumor samples were 100% diploid. These findings suggest that NB exhibits a high degree of clonal heterogeneity and clonal evolution occurs during the course of therapy and clinical progression.

Quick quantitative analysis of gene dosages associated with prognosis in neuroblastoma

The amplification of the N-myc gene and a gain of the chromosome 17q arm correlate with an unfavorable outcome in patients with neuroblastoma. In this study, we determined the gene dosage of the N-myc gene (located at 2p24) and Survivin gene (located at 17q25) using the p53 gene (located at 17p13) as the internal control gene by the TaqMan polymerase chain reaction (PCR)-based gene dosage analysis in 25 neuroblastoma samples. Based on the assumption that the gene dosages of each gene of a normal individual lymphocytes are 1.0, 11 of the 25 cases with a corrected gene dosage of N-myc (N-myc/p53) of more than 2.0 had a more unfavorable prognosis than the 14 cases with a N-myc gene dosage of less than 2.0 (5-year survival rate: 18 vs. 71%, P<0.01). Ten of 25 cases with a corrected Survivin gene dosage (Survivin/p53) of more than 2.0 had a more unfavorable prognosis than the 15 cases with a Survivin gene dosage of less than 2.0 (5-year survival rate: 10 vs. 67%, P<0.01). This quantitative PCR system is considered to be useful for quickly and accurately evaluating the degree of malignancy of neuroblastoma in order to select the optimal treatment.

Biological characteristics of neuroblastoma with partial deletion in the short arm of chromosome 1

BACKGROUND

Neuroblastoma shows remarkable heterogeneity, resulting in favorable and unfavorable outcomes. It is well known that almost all cases with MYCN amplification have a poor prognosis. We have previously reported that unfavorable tumors show high telomerase activity, whereas favorable tumors show low or nil activity. We also found that the unfavorable neuroblastoma often have a loss of heterozygosity (LOH) at the MYCL locus.

PROCEDURE

To clarify the biological and clinical profiles of tumors with genetic abnormalities of the short arm of chromosome 1, we performed deletion mapping on 1p on 92 neuroblastoma tissues and corresponding noncancerous samples obtained from 92 cases for 24 micro- or minisatellite loci.

RESULTS

LOH was detected in at least one locus of 1p in 43 (47%) cases. All samples were classified into four groups according to the deleted pattern: interstitial deletion (group I, n = 20), short terminal deletion (group ST, n = 6), large terminal deletion (group LT, n = 17), and without detectable deletion (group N, n = 49). All group I cases, whose SRO (shortest region of overlap) was at 1p36.1-2, survived disease free, and none of them showed MYCN amplification or high telomerase activity except for one case. On the other hand, in group LT cases, who showed a large terminal deletion from D1S162 (1p32-pter), including the SRO of group 1, only 5 out of 17 have survived disease free, and 13 showed MYCN amplification or high telomerase activity. The six group ST cases showed small terminal deletion from 1p36.3 with modest prognosis, similar to the group N.

CONCLUSIONS

Thus, we propose three loci, 1p36.1-2, 1p32-34, and 1p36.3, as the candidate loci of neuroblastoma suppressor genes on chromosome 1p responsible for groups I, LT, and ST, respectively. Among them, the 1p32-34 locus may be associated with aggressiveness of tumor progression, possibly due to MYCN amplification and/or telomerase reactivation, while the remaining two loci may not.

Fluorescence in situ hybridization techniques for the rapid detection of genetic prognostic factors in neuroblastoma. United Kingdom Children's Cancer Study Group

Neuroblastoma is the commonest extracranial solid tumour in children. There are a number of molecular genetic features known which are of prognostic importance and which are used to direct therapy. Identification and targeting of high-risk individuals with intensive therapeutic regimens may allow an improvement in survival rates. The most powerful biological parameters associated with prognosis in this malignancy are chromosomal changes, especially MYCN amplification, deletion of chromosome 1p and aneuploidy. Rapid characterization of these aberrations at the time of diagnosis is paramount if stratification according to risk group is to be achieved. This paper describes the rapid detection of del(1p), MYCN amplification and trisomy using interphase fluorescence in situ hybridization on imprints from fresh tumour biopsies. The results are related to those obtained by standard molecular methods and karyotyping.

Current aspects of biology, risk assessment, and treatment of neuroblastoma

Neuroblastoma is one of the most intensely studied solid malignancies that affect the pediatric age groups; its clinical presentation, treatment strategies and ultimate prognosis vary greatly. The biologic and genetic character of each tumor has an important impact on disease behavior, and clinical staging now incorporates these factors to generate an overall therapy plan. The clinical presentation of neuroblastoma is related to primary tumor location, production of metabolically active substances, and the presence of metastatic disease. There are also prognostically important associated syndromes including opsoclonus-myoclonus, Horner's syndrome, neurofibromatosis, and a variety of other neurocristopathies. The histologic features of the tumor are of prognostic significance and are utilized in treatment stratification. The International Neuroblastoma Staging System (INSS) has unified classic clinical staging. Features at diagnosis and those determined by initial operation are combined with biologic prognostic factors to achieve risk group assignment for virtually all patients. There are groups of children in which limited therapy is curative and intermediate-risk situations where standard multimodality treatment provides favorable outcomes. Unfortunately, there are many patients with high-risk disease that require intensive strategies, but success is still limited. It is in these most resistant patients that innovative approaches are being undertaken and novel strategies are being investigated.

Composite Pheochromocytoma-Ganglioneuroma of the Adrenal Gland: An Uncommon Entity with Distinctive Clinicopathologic Features

Background: Adrenal composite pheochromocytoma-ganglioneuroma is uncommon. The aim of this study is to investigate the characteristics of patients with this tumor. Methods: Histologic features of 46 pheochromocytomas diagnosed over a 28-year period (1971-1998) were reviewed. The clinical records, pathologic features, and ploidy patterns of patients with composite pheochromocytoma-ganglioneuroma were studied. Cases reported in the literature were also reviewed and compared with typical pheochromocytomas. Results: Four patients (two men; two women) with composite pheochromocytoma-ganglioneuromas were found. The tumors comprised 8.7% of pheochromocytomas. The two male patients with composite tumors were younger than the two female patients (age = 32, 52 vs 73, 75, respectively). The radiologic, gross, and microscopic appearances of the tumors were heterogeneous. One patient had malignant tumor with distant metastases. Flow cytometric analysis showed that the pheochromocytoma component was aneuploid and the ganglioneuroma portion was diploid. A review of the literature showed 31 adrenal composite pheochromocytoma-ganglioneuromas. Composite tumors were seen in older patients and were bigger than typical pheochromocytomas. Conclusion: Composite pheochromocytoma-ganglioneuromas had distinctive clinicopathologic features. Life-long clinical and biochemical follow-up of these patients is essential in view of the non-diploid DNA pattern.

Application of fluorescence in situ hybridization to detect N-myc (MYCN) gene amplification on paraffin-embedded tissue sections of neuroblastomas

Fluorescence in situ hybridization (FISH) was applied to neuroblastoma for detection of N-myc (MYCN) oncogene amplification, and the results were compared with Southern blot analysis (Southern). In nine neuroblastomas (formalin-fixed paraffin-embedded tissues were available in seven cases including two cases with touch preparations, and two cell lines), all five cases with N-myc amplification detected by Southern had cells with multiple N-myc signals by FISH, and three cases showed no N-myc amplification either by Southern or FISH procedure. One case, not examined by Southern, showed amplified signals of N-myc by FISH. These data indicate that FISH results for N-myc amplification have close correlation with Southern blot analysis. The chromosome 2-specific repetitive DNA probe was also applied for the analysis of ploidy by FISH. Six cases with N-myc amplification by Southern and/or FISH had diploid tumors and two cases without amplified N-myc showed aneuploidy. The remaining one case consisted of heterogeneous elements showing diploidy in undifferentiated tissue and both aneuploidy (ganglionic cells) and diploidy (Schwann cells) in differentiated area. We conclude that FISH is a practical, useful and reliable method over Southern especially for analysis of N-myc amplification in neuroblastoma, and simultaneous cohybridization with a specific chromosome probe is of great value in predicting the prognosis of patients.

Role of ploidy, chromosome 1p, and Schwann cells in the maturation of neuroblastoma

BACKGROUND

Neuroblastoma is a heterogeneous disease, with manifestations ranging from spontaneous regression to lethal spread. Sometimes the tumor spontaneously differentiates toward a benign ganglioneuroma (maturing neuroblastoma). The prognosis is frequently related to ploidy, deletions in the short arm of chromosome 1, and amplifications of the N-myc oncogene. Maturing neuroblastomas consist of both neuronal cells and Schwann cells. We investigated the genetic composition of both cell types in maturing neuroblastomas, to determine the relation between genetic abnormalities and maturation.

METHODS

We studied 20 maturing and mature neuroblastomas by in situ hybridization to count the chromosomes and evaluate possible deletions in the short arm of chromosome 1 in neuronal and Schwann cells. The DNA content of the cells was measured by flow cytometry.

RESULTS

Neuroblastic and ganglionic cells showed aberrations in the number of chromosomes. In situ hybridization and flow cytometry demonstrated near-trip-loidy in 18 of 19 tumors and pentaploidy in the remaining tumor. The Schwann cells in all 20 neuroblastomas contained normal numbers of chromosomes. In 18 tumors studied, there were no chromosome 1 deletions in either type of cell.

CONCLUSIONS

The Schwann cells in maturing neuroblastomas differ genetically from the neuronal cells. The normal number of chromosomes in Schwann cells and the abnormal number in neuroblastic ganglionic cells suggests that Schwann cells are a reactive population of normal cells that invade the neuroblastoma. Near-trip-loidy of neuroblastoma cells and intact chromosome 1 are presumably genetic prerequisites for spontaneous organoid maturation, because we found no diploidy or chromosome 1 depletions in the neuronal cells of spontaneously maturing neuroblastomas.

Mass screening for neuroblastoma: quo vadis? A 9-year experience from the Pediatric Oncology Study Group of the Kyushu area in Japan

Since 1985, a nationwide program of mass screening for neuroblastoma has been available for 6-month-old infants throughout Japan. From 1985 to 1993, the authors studied 285 patients with neuroblastoma among their regional population of 15 million. There was an increase in the total number of patients per year in comparison to the previous 6-year period (1979 to 1984). However, no significant difference was noted in the number of patients older than 1 year or in the incidence of advanced-stage (stages III and IV) unscreened cases. The majority of neuroblastomas in the screened group showed favorable biological factors, even in the advanced stages. However, there was a small group with histologically and/or biologically unfavorable factors; five of 115 had amplified N-myc oncogene, four of 74 showed unfavorable Shimada histological findings, and three of 33 had an unfavorable DNA ploidy pattern. One case from this group with unfavorable factors died of the tumor. 3) Thirty-eight cases were negative at the time of mass screening, but later presented with neuroblastoma. Most of them were diagnosed between 1 and 3 years of age, and 30 of the 38 cases (78.9%) were advanced stage with unfavorable prognostic factors. Thus, the authors conclude that mass screening at 6 months can detect a selected population of infants with neuroblastoma; some of the tumors may represent subclinical masses destined for spontaneous regression. However, some tumors with unfavorable factors have been detected by mass screening before progression and/or dissemination. Infants in this group are considered to benefit most from early diagnosis and treatment.

Indolent course of advanced neuroblastoma in children older than 6 years at diagnosis

BACKGROUND

An early observation suggests that children older than 6 years of age at diagnosis of neuroblastoma constitute a favorable prognostic group.

METHODS

Kaplan-Meier plots of survival of all such patients diagnosed at the Children's Hospital of Pittsburgh 1975-1992 were compared with curves of concurrently treated patients with Stage IV disease who were 1-6 years of age at diagnosis ("younger patients"). Known prognostic features, including stage and primary site of disease, pattern of metastases, histopathology, MYCN gene amplification, and urinary catecholamine metabolite ratios, were reviewed.

RESULTS

Of 17 children diagnosed after the age of 6 years ("older patients"), 13 patients had Evans' Stage IV disease and 4 had Stage III disease. The median survival was 3.24 years (range, 0.63-15.04 years) for the entire cohort and 3.07 years for those children with Stage IV disease. This compared with a median survival of 1.05 years in 34 concurrent younger patients (P < 0.01). In most cases, disease in these older patients was characterized by a short-lived complete or partial remission followed by aggressive recurrent disease that was partially and only transiently chemo- or radiosensitive. Only 3 patients (2 with Stage IV disease) are in continuous complete remission at 3, 5 10/12, and 14 1/2 years from diagnosis. Although poor prognostic factors were common, including the presence of bony metastases (12/17), biopsy material from pretreatment tumor specimens demonstrated a single MYCN gene copy number in all patients and favorable histology in 15 of 16 samples.

CONCLUSION

Older children with neuroblastoma have a more indolent course than do younger patients, a finding that appears to be related to favorable histology and the absence of MYCN amplification. Examination of larger numbers of such patients from cooperative groups should lead to a better understanding of what appears to be a subset of pediatric patients with neuroblastoma who may benefit from specifically tailored treatment protocols.

Bcl-2 oncoprotein expression and apoptosis in neuroblastoma

Bcl-2 protooncogene, originally discovered at the chromosomal breakpoint of the t(14;18) in follicular lymphoma, is known to regulate the process of programmed cell death or apoptosis. The inhibition of apoptosis is thought to be one of the mechanisms involved in the development of tumors. To investigate the possible association of bcl-2 protooncogene with the tumorigenesis of neuroblastomas, the authors examined bcl-2 expression by immunohistochemistry in 49 neuroblastomas and 7 ganglioneuromas. The distribution of apoptotic cells was also examined by the TUNEL method (terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling). Bcl-2 oncoprotein was detected in the cytoplasm in 40 of 49 neuroblastomas (81.6%). There was no correlation between bcl-2 oncoprotein expression and the clinical features of neuroblastoma. The incidence of bcl-2-positive tumors in ganglioneuroma was significantly lower than that in neuroblastoma (28.6%) (P < .01). TUNEL stained the nuclei of tumor cells in 11 of 34 (32.4%) neuroblastomas. TUNEL-positive cells tended to be located around calcifications in neuroblastomas in patients less than 1 year old. Examination of serial sections showed that apoptotic cells were distributed in the area where bcl-2 oncoprotein was not expressed. What we have observed indicates that apoptosis of neuroblastoma cells may be regulated by bcl-2 expression. Our observations suggest that the survival of neuroblastoma cells might be promoted by bcl-2 expression and that bcl-2 might be associated with the tumorigenesis of neuroblastomas.

Relationship between DNA ploidy level and tumor sociology behavior in 12 nervous cell lines

Cell population sociology was studied in two medulloblastomas and 10 astrocytic human tumor cell lines by means of the characterization of the structure of neoplastic cell colonies growing on histological slides. This was carried out via digital cell image analysis of Feulgen-stained nuclei, to which the Delaunay triangulation and Voronoi paving mathematical techniques were applied. Such assessments were compared to the DNA polidy level (assessed by means of DNA histogram typing). The results show that the cell colony architecture characteristics differed markedly according to whether the cell lines were euploid (diploid or tetraploid) or aneuploid (hyperdiploid, triploid, hypertriploid, or polymorphic). In fact, the cell colonies from the euploid cell nuclei populations were larger and more dense than those from the aneuploid ones. Furthermore, for an identical period of culture, the cell lines from high-grade malignant astrocytic tumors (glioblastomas) exhibited cell colonies that were larger and more dense than those in cell lines from low-grade astrocytic tumors (astrocytomas). In each of these two groups, the diploid cell nuclei populations exhibited cell colonies larger and more dense than the nondiploid colonies. The present methodology is now being applied in vivo to histological sections of surgically removed human brain tumors in order to distinguish between high-risk clinical subgroups and medium-risk subgroups in clearly circumscribed histopathological groups.

Neuroblastoma in infants aged less than 6 months: is more aggressive treatment necessary? A report from the Pediatric Oncology Study Group of the Kyushu area

Infants with neuroblastoma are known to have a better prognosis than older children. In Japan in 1985, mass screening for neuroblastoma in infants aged 6 months was introduced. With this policy, there has been an increase in the number of patients seen with neuroblastoma between 6 and 11 months of age. In a previous report the authors described the management and prognosis of infants with disease detected by mass screening, but there is still little information regarding the strategies of management for infants with neuroblastoma aged less than 6 months. The authors analyzed the data regarding 27 patients aged less than 6 months registered in their region (population 15 million) from 1985 to 1992, and compared it with that of the previous 8-year period. In the younger age group, there was a significantly higher rate of advanced disease stages (III and IV). In spite of the variation in treatment related to the choice of individual institutions, infants with stages I, II, and III disease had a good outcome, suggesting that aggressive chemotherapy is not necessary unless poor prognostic factors are present. One patient with stage IV disease died of disseminated disease and one with stage IVs and 22 copies of N-myc oncogene also died of tumor relapse in spite of aggressive chemotherapy. It is therefore concluded that the prognosis in infants with stage IV and IVs neuroblastoma under the age of 6 months is not as good as had previously been believed, and that such patients, therefore, require special consideration.

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.

Morphologic and molecular cytogenetics in neuroblastoma

BACKGROUND

Some genetic alterations have been shown to have prognostic implication for patients with neuroblastoma: MYCN oncogene amplification, deletion of the short arm of chromosome 1 and di- or tetraploidy. The goal of this study was to analyze these factors in children with neuroblastoma.

METHODS

Twenty neuroblastoma samples were analyzed with morphologic cytogenetics, and each of them was compared with MYCN amplification status by Southern blot and fluorescent in situ hybridization (FISH) with a genomic probe.

RESULTS

A complete karyotype was obtained for 14 children. A diploid or tetraploid mode and a 1p deletion were found in most children with advanced stages. MYCN amplification status was totally concordant with both methods in all patients, even in a case with low level amplification. A wide intercellular variation in the amplification level in each MYCN amplified sample was shown.

CONCLUSION

The use of FISH to assess MYCN amplification rapidly in neuroblastoma is recommended. This method could be very useful in future therapeutic protocols in which treatment is based on MYCN status (and especially for infants and children with localized tumor).

Correlation of DNA content between endoscopic biopsy and surgically resected specimens in gastric and colorectal cancer

To investigate DNA heterogeneity and the consistency of DNA content between endoscopic biopsy and the corresponding resected specimens, the DNA content of 749 different samples from 30 gastric and 30 colorectal cancers was analyzed and the results were compared with those obtained from endoscopic biopsy specimens. The incidence of DNA heterogeneity was 33% in patients with gastric cancer and 40% in those with colorectal cancer. Most of the cases of heterogeneity were caused by differences in DNA indices in aneuploidy. The consistency of DNA ploidy pattern between endoscopic biopsies and the corresponding resected specimens was 100% in both gastric and colorectal cancer, while the consistency in the DNA index of aneuploid tumors was approximately 90%. From these results, it seems possible that analysis of the DNA content of a biopsy specimen could provide an adequate measure of the DNA content of the corresponding resected specimen.

Age-related profile of neuroblastoma: a comparison of tumors detected by mass-screening with those detected clinically

Infants with neuroblastoma are known to have a favorable prognosis compared to those over 1 year of age. However, there is little biological information about the age-related heterogeneity of neuroblastoma. We evaluated the biological profile comparing cases detected by mass screening with those detected clinically. A total of 238 patients with neuroblastoma were classified into four groups according to their age at diagnosis. Patients in group A were 0-5 months of age (n = 31). Patients in group B were detected clinically and were 6-11 months of age (n = 25). Patients in group C were 6-11 months of age and were detected by mass-screening (n = 97). Patients in group D were more than 12 months of age (n = 85). The age-related heterogeneity was evaluated by Kaplan-Meier survival analysis, several clinical markers (neuron specific enolase, ferritin, vanillylmandelic acid and homovanillic acid) at diagnosis, tumor Ha-ras p21 expression and tumor N-myc amplification. Infant neuroblastoma had unique features in comparison to neuroblastoma diagnosed over 12 months of age. Clinical outcome of the patients in groups A and C was quite favorable. Even patients with stage III or IV disease in group A had a favorable prognosis. However, stage IVs disease in group A was not necessarily associated with a good prognosis and the early death after diagnosis was also characteristic. The biological profile of tumors in group C was similar to that in group A but different from the profile in groups B and D. Tumors in group B had a biological profile intermediate between groups A and D.(ABSTRACT TRUNCATED AT 250 WORDS)

Schwann cells in neuroblastoma

Why should we consider Schwann cells when we are interested in the biology of neuroblastomas (NBs)? Although we are familiar with the term "stroma-rich" NB, we basically think of a favourable prognostic subgroup, histologically distinguished by the development of a prominent Schwann cell-stroma. According to current opinion on the maturation processes in NBs, the NB-associated Schwann cell is believed to represent a differentiation product of the NB cell, and we therefore do not envisage the Schwann cell as having any important role in NBs. However, our interest was raised after having realised that Schwann cells in NBs are normal cells, very likely attracted to the neoplastic neuroblasts. But what role does this cell play in these tumours? Can we still reduce the appearance of Schwann cells in NBs to an epi-phenomenon or is this cell population responsible for the differentiation of certain NBs? If so, will it be possible to use their strategies to induce differentiation of neuroblasts and so render them non-aggressive, mature ganglionic cells? To shed light on the possible interactions between normal Schwann cells and NB cells, the maturation capacity of NBs and the genetic constitution of the two main cell populations in these tumours are briefly reviewed. Some data leading to the current view on the origin of the Schwann cells in NBs, and several physiological aspects of the Schwann cells, including normal neurone-Schwann cell interactions, are detailed.

Molecular basis for heterogeneity in human neuroblastomas

Neuroblastomas demonstrate both clinical and biological heterogeneity. We have proposed that neuroblastomas may be classified in three genetically distinct subtypes, based on cytogenetic and molecular analysis. The first comprises those with hyperdiploid or triploid modal karyotypes (or compatible DNA content by flow cytometry), 1p LOH and MYCN amplification are absent, and TRKA expression is high. These patients are likely to be infants with low stages of disease (stages 1, 2, or 4S by the International Neuroblastoma Staging System), and they have a very favourable outcome (> 90% cure). The second group consists of tumours that generally have a near diploid or tetraploid modal chromosome number or DNA content but lack MYCN amplification. They usually have 1p allelic loss, 14q allelic loss or other structural changes, and TRKA expression is usually low. These patients are generally older with advanced stages of disease (stages 3 or 4), and they have a slowly progressive course, with a cure rate of 25-50%. The third group is characterised by tumours with MYCN amplification. These tumours are generally near diploid or tetraploid, with 1p allelic loss, and low or absent TRKA expression. The patients are usually between 1 and 5 years of age with advanced stages of disease, and they have a very poor prognosis (< 5%). It remains to be determined if tumours in one group ever evolve into a less unfavourable group, but current evidence suggests that they are distinct genetically. The identification of the oncogenes, suppressor genes and growth factor receptor pathways involved in neuroblastomas has provided great insight into the mechanisms of malignant transformation and progression, and ultimately they may provide the targets for future therapy.

Regression and progression in neuroblastoma. Does genetics predict tumour behaviour?

Neuroblastoma (NB) is a heterogeneous disease. The clinical course may range from spontaneous regression and maturation to very aggressive behaviour. Stage 4s is a unique subcategory of NB, generally associated with good prognosis, despite skin and/or liver involvement and the frequent presence of tumour cells in the bone marrow. Another type of NB is the locally invasive tumour without bone and bone marrow involvement which can also have a good prognosis, irrespective of lymph node involvement. Unfortunately, there is only limited biological information on such tumours which have not been treated with cytotoxic therapy despite lymph node involvement, residual tumour mass after surgery and/or bone marrow infiltration. In order to find specific genetic changes common to NBs with a benign clinical course, we studied the genetic abnormalities of these tumours and compared them with highly aggressive tumours. We analysed a series of 54 localised and stage 4s tumours by means of in situ hybridisation performed on fresh cells or on paraffin embedded tissues. In addition, we performed classical cytogenetics, Southern blotting and PCR analysis on fresh tumour tissue. The majority of patients had been treated with surgery alone, and in a number of patients tumour resection was incomplete. Deletions at 1p36 and amplifications of the MYCN oncogene were absent, and diploidy or tetraploidy were not seen in any case, with residual localised tumours possessing a favourable outcome. Unexpectedly, one patient with a tetraploid 4s tumour without any genetic structural changes not receiving any cytotoxic treatment, did well. Interestingly, this genetic spectrum contrasted with that of progressing tumours, in which most had genetic aberrations, the deletion at 1p36 being the most common event. These data, although limited, suggest that an intact 1p36 (recognised by D1Z2), the absence of MYCN amplification and near-triploidy (at least in localised tumours), represent prerequisites for spontaneous regression and/or maturation.

Poor outcome in patients with advanced stage neuroblastoma and coincident opsomyoclonus syndrome

BACKGROUND

Most patients with neuroblastoma who present with opsomyoclonus have a good prognosis. Neuroblastomas from such patients have been reported to contain a single copy of the N-myc gene. The authors describe three cases of patients with advanced neuroblastoma with opsomyoclonus, which had poor outcomes despite multimodal therapy.

METHODS

Amplification and expression of the N-myc gene were examined in these three primary tumors using Southern and Northern blot analyses. Then, flow cytometric analysis of the cellular DNA contents of these tumors was performed.

RESULTS

N-myc amplification was observed in two tumors and N-myc RNA overexpression was observed in all three. Analysis of the cellular DNA contents of the tissue specimens revealed hyperdiploidy in all three tumors; one had a triploid index and the other two had hypotetraploid indexes.

CONCLUSIONS

These findings suggest that a poor outcome for patients with opsomyoclonus may be associated with N-myc gene activation (amplification and/or overexpression) and that a hyperdiploid tumor is not always associated with a good prognosis.

Screening for neuroblastoma: a review of the evidence

Screening infants for the early detection of neuroblastoma is advocated by many paediatric oncologists and is practised in a limited number of places in the developed world, most notably in Japan where a national screening programme has been in operation since 1985. The screening test consists of measurements of the levels of vanillylmandelic acid and homovanillic acid in the urine; these metabolites of catecholamine are excreted in the urine of 92% of patients with clinically presenting neuroblastoma. The prognosis for children with symptomatic neuroblastoma is dependent both on age and stage, with children aged under 1 year and those with tumours of stages I, II, and IVS having a much better prognosis. Screening aims at detecting and treating during the first year those neuroblastomas which would otherwise present at an advanced stage in older children. Evidence from Japan shows that screening achieves the interim outcomes of a shift in the age distribution and stage distribution of neuroblastomas in populations for whom screening has been provided, and that survival of subjects detected by screening is over 90%, compared with around 50% for symptomatic subjects. However, there is not yet any clear evidence that screening results in a reduction in the incidence of advanced neuroblastoma in children over the age of 1, nor a reduction in mortality. Recent cross sectional analyses of age specific incidence and mortality suggest that screening may be having a limited effect, but as yet no analysis of these outcomes in cohorts for whom screening has been provided has been published. Other factors, such as improved chemotherapy, may also be contributing to lower mortality. A number of missed (interval) cancers have been diagnosed in children who screened negative both in the Japanese programme and in Canadian and English studies, indicating that there is a problem with the sensitivity of screening. But the screening test is highly specific with less than 0.1% of infants having false positive results requiring investigation. The natural history of neuroblastoma ranges from highly malignant tumours to biologically benign variants that regress without active treatment, the prevalence of the latter being inversely related to age. Serial measurements of biological markers, including ploidy, chromosome 1p deletion, and N-myc amplification, performed within the same patient at different times indicate that malignant potential does not progress over time. The distribution of these markers in cases detected by screening shows that they are inherently tumours with a good prognosis, whereas the reverse is true of interval cases. Thus screening is differentially picking up the tumours that are least likely to progress and failing to detect at least some tumours of those destined to die from the disease. Comparison of the yield of cancers detected by screening and the expected cumulative incidence of neuroblastoma throughout childhood suggest that screening "overdiagnoses" many non-progressive cases, with consequent physical and psychological morbidity. On balance present evidence suggests that the number of deaths that could be prevented by screening is small and the potential for overdiagnosis is great. Unless further evidence from Japan or the results of a current North American trial conclude otherwise, screening cannot be recommended.

What is the benefit of aggressive chemotherapy for advanced neuroblastoma with N-myc amplification? A report from the Japanese Study Group for the Treatment of Advanced Neuroblastoma

In 1985, a nationwide single protocol (cyclophosphamide, vincristine, tetrahydropyranyl Adriamycin, and cisplatin) for the treatment of advanced neuroblastoma was begun in Japan and was found to significantly increase the 3-year survival rate--to 70% for stage III, and to 45% for stage IV. In this study, the authors investigated the efficacy of this protocol for advanced neuroblastoma with or without N-myc amplification. In 159 of the 233 patients with advanced neuroblastoma treated with this protocol (between January 1985 and March 1993), genomic amplification of N-myc was determined. These 159 patients were divided into two groups according to the number of N-myc copies, ie, those with fewer than 10 copies (105 patients) and those with 10 or more copies (54 patients). The survival curves for the two groups were significantly different. The 5-year survival rate for patients with 10 or more copies was 43.9%; this is surprisingly high in comparison to results of previous studies in which no survivors were expected in cases of advanced neuroblastoma with highly amplified N-myc. Persistent bone marrow suppression was common, but there were no deaths attributable to drug side effects. Five patients with fewer than copies of N-myc amplification died more than 3 years after initial treatment. Three of the five had tumors with an unfavorable Shimada classification, and two had diploid nuclear DNA content. The authors conclude that the protocol resulted in dramatic improvement in the patients with advanced neuroblastoma, even with high N-myc amplification.(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic scoring in adult astrocytic tumors using patient age, histopathological grade, and DNA histogram type

High-grade astrocytic tumors constitute the most serious as well as the most common group of primary brain tumors. Although several prognostic factors have been proposed, little is known about the prognostic value of deoxyribonucleic acid (DNA) ploidy in adult astrocytic tumors. In a series of 146 adult patients, aged 16 to 82 years, the individual prognostic values of six variables were studied, namely: tumor histopathological grade, treatment, patient age, extent of tumor, ploidy level, and DNA histogram type. Cox's proportional hazard model was then applied to the data to ascertain which factors might independently determine patient survival. Univariate analyses revealed that histopathological grade, age, and DNA histogram type were very powerful prognostic factors. The statistical significance of the influence of adjuvant radiotherapy and chemotherapy was at a borderline level, and the two remaining variables (tumor extent and ploidy level) had no prognostic relevance. Multivariate analyses showed that age, histopathological grade, and DNA histogram type were independent, statistically significant prognostic factors. A prognostic score was calculated from Cox's polynomial function in which those factors were introduced. The best score corresponded to a patient aged 16 years with a hypertriploid low-grade astrocytoma, while the worst score corresponded to a patient aged 82 years with a diploid high-grade astrocytoma. The worst score:best score ratio revealed a risk 71 times higher for a bad prognosis. It is concluded that patient age, histopathological grade, and DNA histogram type are very powerful prognostic factors for adult astrocytic tumors. A prognostic score including those factors could be used to characterize astrocytic tumor aggressiveness presurgically on fine-needle aspirates, and to monitor the patient's postsurgical evolution to define the appropriate therapy.

How to deal with advanced cases of neuroblastoma detected by mass screening: a report from the Pediatric Oncology Study Group of the Kyushu area of Japan

Since 1985, a nationwide program of mass screening (MS) for neuroblastoma has been underway for 6-month-old infants throughout Japan. As a result, the number of patients with stage I or II disease has obviously increased, and this has resulted in overall improvement of the prognosis for neuroblastoma. Some cases detected by MS were already in an advanced stage and have also had a good prognosis. In such cases, no definitive treatment protocol has been developed. Therefore, the authors investigated (1) the clinical and biological features of the advanced neuroblastoma cases detected by MS and (2) the best way to deal with such cases. The authors analyzed 94 cases of advanced-stage neuroblastoma registered in the Kyushu area (population, 15 million) between 1985 and 1990. Eighteen cases (16 stage III, 2 stage IV) were found by MS, and the others (23 stage III, 53 stage IV) were diagnosed clinically. The following results were obtained: (1) No N-myc amplifications were observed in cases detected by MS, whereas 16 of the 45 examined patients in the non-MS group had high amplifications of N-myc. (2) With regard to Shimada's classification, DNA content, and S-100 protein positivity, most of the advanced tumors found by MS showed characteristics indicating a good prognosis. (3) The 5-year survival rate for the non-MS group is less than 25%, whereas all of the patients whose tumors were detected by MS are alive, even after undergoing mild chemotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA flow cytometric analysis of neuroblastoma: distinction of tetraploidy subset

Neuroblastoma has several characteristics that differentiate it from other adult malignancies. The ploidy pattern of neuroblastoma has been shown to be related to prognosis. Specifically, a DNA diploidy pattern is associated with a poorer outcome, and an aneuploidy pattern is associated with a better outcome. A tetraploidy pattern has also been identified; however, there is little information regarding this pattern. To examine the properties of neuroblastoma according to these DNA ploidy patterns, the authors performed flow cytometric analysis (retrospectively) for 61 neuroblastoma cases, using paraffin-embedded tissues. Fifty-six of the cases had analyzable results. Calculated DNA indices (DI) ranged from 1.0 to 2.30. The 56 cases were divided into three groups according to DI: diploid (DI = 1.0 to 1.17, n = 19), aneuploid (DI = 1.25 to 1.75, n = 26), and tetraploid (DI = 1.81 to 2.30, n = 11) groups. Compared with the aneuploid group, the diploid group had a stronger correlation with older patient age (> or = 1 year) (P < .01), more advanced clinical stage (III, IV) (P < .01), and poorer prognosis (P < .001). The tetraploid group had properties that were statistically similar to those of the diploid group (P < .05, P < .05, P < .001, respectively). These findings indicate that a subset of DNA tetraploid is present in neuroblastoma, and this subset, which may have clinical and biological characteristics similar to those of the DNA diploid group, should be distinguished from DNA aneuploidy.

Assessment of nuclear size, nuclear DNA content and proliferation index in stereotaxic biopsies from brain tumours

In this paper we study the feasibility of measuring the diverse biological parameters in stereotaxic biopsies from human brain lesions. These biological parameters are the nuclear area (NA), the proliferation index (PI) and the ploidy level, the latter of which was evaluated by means of the DNA index (DI) and histogram type (DHT). These parameters were assessed by means of the digital cell image analysis of Feulgen-stained nuclei. This analysis was performed on 124 samples from 22 computed tomography (CT)-guided stereotaxic biopsies. The data show that the methodology used here enables the above parameters to be assessed on small samples without limiting the classical anatomopathological diagnosis. The data also reveal that the DHT corresponded more accurately to the ploidy level in the sample analysed than the DI. Lastly, it appears that supratentorial astrocytic tumours of the adult, which constituted the majority of the cases analysed here, are strongly heterogeneous at a biological level.

Combined determination of N-myc oncogene amplification and DNA ploidy in neuroblastoma. Complementary prognostic indicators

BACKGROUND

N-myc gene amplification is a well-established prognostic indicator in neuroblastoma. Flow cytometric analysis of nuclear DNA content has shown that an abnormal nuclear DNA content in neuroblastoma is associated with a better prognosis. Because some patients with N-myc unamplified tumors have a poor prognosis, factors other than N-myc amplification may play a role in determining the clinical behavior of neuroblastoma. In the current study, the authors correlated N-myc gene amplification and flow cytometric nuclear DNA content with respect to prognosis.

METHODS

Forty-one patients with neuroblastoma, including 15 screened patients, served as subjects. The copy number of the N-myc gene was determined by Southern blot analysis. DNA ploidy analysis was done on nuclei isolated from formalin-fixed, paraffin-embedded blocks.

RESULTS

Of 40 specimens of neuroblastoma, 7 involved tumors containing amplification of the N-myc gene and 33 did not; 13 specimens showed DNA diploidy, and 27 showed DNA aneuploidy (including 4 with DNA tetraploidy). The Kaplan-Meier survival analysis indicated a significantly better prognosis in patients with unamplified N-myc tumors compared with those with N-myc amplified tumors (87.3% versus 28.6%, P < 0.05) and in patients with DNA aneuploid tumors compared with those with DNA diploid tumors (96.3% versus 43.0%, P < 0.001). The difference in the survival of the two extreme combinations, (e.g., 25 with N-myc unamplified and DNA aneuploidy [4 tetraploidy] versus 5 with N-myc amplified and DNA diploidy) was more significant (96.0% versus 20.0%, P < 0.001) than any other combination.

CONCLUSION

Evaluations of N-myc gene amplification and DNA ploidy are complementary, and the combined determination of these two factors may be one of the most powerful prognostic indicators in neuroblastoma.

Flow cytometric DNA analyses of frozen samples from children's solid tumors

Cell ploidy and proliferative activity may be useful to clinicians in treating children with solid tumors. Frozen specimens from children with malignant solid tumors were tested at the time of diagnosis for ploidy and proliferative activity. The flow cytometric DNA histograms were examined to assess the sensitivity of the tumor cell preparation and staining method. All the frozen tumors received (n = 58), from children aged 1 mth to 17 yrs, were analyzed and included in this study. The more common tumors were neuroblastomas (n = 21) and Wilms' tumors (n = 16). The majority of tumors (91%) exhibited a diploid peak from the significant proportion of stromal/epithelial cells in the tumor specimen. The tightness of the diploid G0G1 peaks as measured by their coefficient of variations (CV) produced a mean CV of 2.43% +/- SD 0.62, range 1.3% to 4.6%. The G0G1 CVs from the aneuploid peaks had a mean of 2.34% +/- SD 0.68 with the range 0.5% to 3.7%. There was, however, a proportion of tumors (9%) which showed no normal "diploid" peak on the histogram. These tumor cell suspensions had insignificant numbers of diploid cells. Unless the position of the diploid peak could be identified on the DNA histogram the ploidy result from such tumors would be incorrect. Reference diploid cells can be added to cell suspensions prepared from frozen tumors in order to identify the position of the G0G1 peak. Reference diploid cells cannot be added to single cell preparations from paraffin embedded specimens, therefore making it impossible to define the diploid peak position in these tumors.(ABSTRACT TRUNCATED AT 250 WORDS)

Ploidy changes between diagnosis and relapse in childhood renal tumours

Ploidy patterns, analysed by flow cytometry (FCM) and image analysis (IA), were investigated at relapse in a group of six children with renal tumours [five Wilms' tumour (WT) and one bone metastasizing renal tumour of childhood (BMRTC)] and results compared with diagnostic profiles. IA detected one or more aneuploid populations in five of 12 tumours which were diploid on FCM. Patterns in three of six patients [two with unfavourable histology (UH) and one with favourable histology (FH)] were aneuploid at diagnosis and relapse, two patients (one FH, one BMRTC) developed aneuploid features at relapse and one patient with a tetraploid tumour was diploid at relapse. Histology patterns were similar at diagnosis and relapse in all patients. Three of six patients (two UH, one BMRTC) have died of disease. This report highlights (1) the superiority of IA over FCM in detecting aneuploid populations and (2) changes in ploidy status which have not previously been reported in these tumours. Overinterpretation of DNA status at relapse may prove misleading.

Flow cytometric DNA analysis of interleukin-2 responsive renal cell carcinoma

Adoptive immunotherapy using interleukin-2 (IL-2) based therapy can result in marked tumor regression in some patients with metastatic renal cell carcinoma. DNA flow cytometry has not been previously studied as a predictor of outcome of this therapy. Archival paraffin embedded tumors were studied in 23 IL-2 treated patients with metastatic renal cell carcinoma. Eleven patients were complete responders (CR) and 12 were nonresponders (NR). In the CR group, 4/11 (40%) were diploid and 7/11 (60%) were aneuploid. In the NR group, 9/12 (75%) were diploid and 3/12 (25%) were aneuploid. Although there was a trend that patients with an aneuploid DNA pattern were more likely to undergo a complete response, ploidy pattern alone was not significantly predictive of response (p2 = 0.10, Fischer's exact test). When combining ploidy pattern with other variables that were predictive for complete response, such as good performance status and a higher pretreatment weight, prediction of complete response was not improved by including ploidy. This preliminary report suggests that DNA ploidy does not appear to provide any additional information concerning responsiveness to IL-2 based immunotherapy beyond that obtained by performance status and pretreatment weight in this patient population.

Comparative clinical evaluation of biochemical and genomic tumor markers

The clinical utilities of established biochemical tumor markers and of emerging genomic markers are compared by six formal criteria: [1] tests negative in health or benign disease, [2] produced exclusively by specific tumor cells, [3] present frequently in the targeted malignancy, [4] detectable in occult disease, [5] degree of expression reflects tumor burden and prognosis, and [6] degree of expression correlates with therapeutic result. Evaluation of eight widely accepted marker systems combining a biochemical indicator with a specific cancer, on the one hand, and five representative genomic marker-target combinations involving chromosomal translocation, gene amplification and mutation, on the other hand, produces three main conclusions: First, specified applications are sufficiently well documented for the best biochemical markers to now tailor analytical performance goals to these uses. Second, further clinical trials of genomic markers are needed to document the useful linkage of specific indicators with specific clinical problems. Third, the different profiles of marker characteristics defining the two classes of indicators suggest some mutually complementary uses.

Association between high levels of expression of the TRK gene and favorable outcome in human neuroblastoma

BACKGROUND AND METHODS

The nerve growth factor receptor is expressed in some neuroblastomas, in which its primary component is encoded by the TRK protooncogene. To determine the relation of the expression of TRK messenger RNA in neuroblastomas to other clinical and laboratory variables, we studied frozen tumor samples from 77 patients. In addition, we tested two primary neuroblastomas that expressed TRK for responsiveness to nerve growth factor.

RESULTS

TRK expression strongly correlated with favorable tumor stage (I, II, and IVS vs. III and IV), younger age (< 1 year vs. > or = 1 year), normal N-myc copy number, and low level of N-myc expression. N-myc amplification (indicated by a high copy number) correlated with advanced tumor stage, older age, an adrenal site of the primary tumor, low level of expression of TRK, and high level of expression of N-myc. Analysis of five-year cumulative-survival rates demonstrated an association of a very favorable outcome with a high level of TRK expression (86 percent vs. 14 percent) and with normal N-myc copy number (84 percent vs. 0 percent). Univariate analysis showed that these two variables were the most powerful predictors of outcome (chi-square = 51.30, P < 0.001; and chi-square = 93.61, P < 0.001, respectively). TRK expression still had significant prognostic value when the analysis was restricted to tumors without N-myc amplification. In primary cultures of neuroblastoma cells expressing TRK, exposure to nerve growth factor induced early gene expression and neurite outgrowth, but deprivation of nerve growth factor led to neuronal cell death.

CONCLUSIONS

A high level of expression of the TRK proto-oncogene in a neuroblastoma is strongly predictive of a favorable outcome. A tumor with a functional nerve growth factor receptor may be dependent on the neurotrophin nerve growth factor for survival and may regress in its absence, allowing a new approach to the treatment of certain patients with neuroblastoma.

Neuroblastoma. Effect of genetic factors on prognosis and treatment

BACKGROUND AND METHODS. Genetic analysis of tumor tissue has provided considerable insight into mechanisms of malignant transformation and progression. Neuroblastomas have been studied by cytogenetics, flow cytometry, and molecular genetic techniques, and these studies have identified several specific abnormalities that allow subclassification of these tumors into genetic/clinical subtypes. RESULTS AND DISCUSSION. Four genetic abnormalities have been identified that are characteristic of certain neuroblastomas. These include: (1) loss of heterozygosity (LOH) for the short arm of chromosome 1, including band 1p36; (2) amplification of the N-myc protooncogene; (3) hyperdiploidy, or near triploidy; and (4) defects in expression or function of the nerve growth factor receptor (NGFR). Abnormalities of the NGFR are found in virtually all neuroblastoma cell lines, and some primary tumors. The latter have not been studied extensively. Hyperdiploidy is associated with lower stages of disease and with a favorable outcome in infants. LOH for chromomors. The latter have not been studied extensively. Hyperdiploidy is associated with lower stages of disease and with a favorable outcome in infants. LOH for chromosome 1, band p36, and N-myc amplification are more common in patients older than 1 year of age with advanced stages of disease. The latter two genetic abnormalities may be related, and LOH for 1p36 may precede the development of amplification. When these abnormalities are combined with assessment of DNA content, three distinct genetic subsets of neuroblastomas can be identified. The first is characterized by a hyperdiploid or near-triploid modal karyotype, with few if any cytogenetic rearrangements. These patients generally are younger than 1 year of age with localized disease and a good prognosis. The second has a near-diploid karyotype, with no consistent abnormality identified currently. These patients generally are older with more advanced stages of disease that progress slowly and are often fatal. The third group has a near-diploid or tetraploid karyotype, with deletions or LOH for 1p36, amplification of N-myc, or both. These patients generally are older with advanced stages of disease that rapidly are progressive. Thus, genetic analysis of neuroblastoma cells provides information that has prognostic significance and can direct a more appropriate choice of treatment.

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.