Original article
Favorable outcome of triploid neuroblastomas: a contribution to the special oncogenesis of neuroblastoma

https://doi.org/10.1016/j.cancergencyto.2005.09.001Get rights and content

Abstract

There is a well-known association between patient outcome and tumor ploidy in neuroblastoma. To date, however, most clinical trials have not used this parameter for therapy stratification. Using conventional cytogenetics and fluorescence in situ hybridization (FISH), we investigated 36 tumors in terms of ploidy and chromosome 1 copy number (polysomy). In addition, interphase FISH for polysomy was performed on a second cohort of 440 neuroblastomas, together with the status of 1p, MYCN, and 11q. The main goals were as follows: (1) to assess the reliability of FISH to determine ploidy; (2) to illustrate associations between somy 1 and clinical/biologic factors; and (3) to investigate the role of somy 1 for predicting outcome. The comparison between karyotyping and FISH in the smaller cohort revealed 86% consistency between ploidy and polysomy (31/36). According to FISH, trisomic tumors in the second cohort showed structural chromosomal aberrations less frequently compared to di-/tetrasomic tumors (15 vs. 60%, P < 0.001). The portion of trisomic neuroblastomas was higher in stages 1, 2, and 4S versus stages 3 and 4 (55 vs. 24%, P < 0.001) and in children 18 months or younger versus those older than 18 months (55 vs. 19%, P < 0.001). Prognosis was significantly better for trisomic tumors versus di-/tetrasomic in the whole cohort [event-free (EFS) and overall survival (OS), P < 0.001]. In the subgroup without abnormalities of other molecular markers, EFS of trisomic neuroblastomas was better (P = 0.048), but was most likely due to an unequal stage distribution. In further subgroups, in terms of age and stage, significance between the somy groups was not reached, neither for EFS nor OS. The multivariate analyses including age, stage, chromosomal markers, and somy 1 confirmed the lack of independent prognostic power for the copy number of chromosome 1. This study demonstrates the following: (1) FISH is a practical alternative to other more labor-intensive techniques for determining ploidy; (2) trisomic tumors correlate with younger age at diagnosis, localized stage, and the lack of structural alterations; and (3) polysomy is not an independent prognostic marker. The sharp decline of trisomic tumors after the age of 18 months supports the idea of different genetic tumor entities.

Introduction

In several publications during the last 20 years, ploidy of neuroblastoma cells was considered a central marker that predicted prognosis. Early cytogenetic studies showed a high frequency of structural alterations in tumors with a near-diploid or near-tetraploid karyotype, whereas near-triploid cases frequently lacked these changes [1]. Karyotype analyses of a larger series of favorable tumors diagnosed after neuroblastoma screening displayed many near-triploid cases [2]. Further ploidy analyses were performed using flow cytometry. Look et al. [3], [4] indicated an association between hyperdiploidy and long-term survival after treatment for children below 2 years of age. In contrast, a diploid content correlated with early treatment failure. Although other groups obtained similar results [5], [6], [7], [8], tumor ploidy has not been implemented as a therapy stratification parameter in all but one international study. The exception has been the U.S. Pediatric Oncology Group trials, where ploidy discriminates between intermediate- and low-risk treatment for patients with nonamplified stage 4S.

In this study, we performed karyotype analyses in combination with interphase fluorescence in situ hybridization (FISH) on a cohort of 36 neuroblastoma patients to ascertain the consistency between tumor ploidy and the polysomy status of chromosome 1 according to FISH. In addition, a second collective of 440 specimens was investigated using FISH to ascertain associations of polysomy 1 with the patient's age, stage, and structural chromosomal alteration, and to assess the prognostic influence of polysomy 1.

Section snippets

Materials and methods

A series of 36 neuroblastoma tumors were investigated using both karyotype analysis and interphase FISH. Tumor samples were processed as described in Betts et al. [9]. In a second cohort consisting of 440 neuroblastoma patients, the copy number of chromosome 1 as well as the status of 1p, 11q, and MYCN were determined according to interphase FISH. Tissue samples were collected in 85 hospitals in Germany and Switzerland which were participating in German cooperative trials NB90/NB95 and NB97.

Results

The results of conventional karyotyping and interphase FISH of our first cohort of 36 neuroblastoma samples are summarized in Table 1. The copy number of chromosome 1 assessed by FISH corresponded to the ploidy level in 31/36 patients (86%). Three near-diploid tumors and one near-tetraploid tumor displayed three copies of chromosome 1 according to FISH, and one near-triploid neuroblastoma showed a tetrasomy 1.

The polysomy status of chromosome 1, together with the status of 1p, 11q, and MYCN

Discussion

In a large series of 151 neuroblastomas, Kaneko et al. [13] described the relationship between the modal chromosome number and the number of chromosomes 1. Due to the close correlation between these parameters, the authors concluded that tumors with disomy or trisomy 1 might be considered as diploid or triploid. The present analyses of 36 tumors using FISH and chromosome karyotyping confirmed this observation with very similar findings. Therefore, we assessed the copy number of chromosome 1 by

Acknowledgments

This work was supported by the Deutsche Kinderkrebsstiftung e.V. and Tumour Bank Neuroblastoma of the competence network Paediatric Oncology and Haematology (KPOH).

References (24)

  • D.R. Betts et al.

    Routine karyotyping in Wilms tumor

    Cancer Genet Cytogenet

    (1997)
  • T. Kusafuka et al.

    DNA flow cytometric analysis of neuroblastoma: distinction of tetraploidy subset

    J Pediatr Surg

    (1994)
  • F. Westermann et al.

    Genetic parameters of neuroblastomas

    Cancer Lett

    (2002)
  • B.R. Brinkley

    Managing the centrosome numbers game: from chaos to stability in cancer cell division

    Trends Cell Biol

    (2001)
  • Y. Kaneko et al.

    Different karyotypic patterns in early and advanced stage neuroblastomas

    Cancer Res

    (1987)
  • Y. Kaneko et al.

    Current urinary mass screening for catecholamine metabolites at 6 months of age may be detecting only a small portion of high-risk neuroblastomas: a chromosome and N-myc amplification study

    J Clin Oncol

    (1990)
  • A.T. Look et al.

    Cellular DNA content as a predictor of response to chemotherapy in infants with unresectable neuroblastoma

    N Engl J Med

    (1984)
  • A.T. Look et al.

    Clinical relevance of tumor cell ploidy and N-myc gene amplification in childhood neuroblastoma: a Pediatric Oncology Group study

    J Clin Oncol

    (1991)
  • F.M. Massara et al.

    Prognostic factors in neuroblastoma

    Pediatr Med Chir

    (1996)
  • J. Bourhis et al.

    Combined analysis of DNA ploidy index and N-myc genomic content in neuroblastoma

    Cancer Res

    (1991)
  • S.L. Cohn et al.

    Analysis of DNA ploidy and proliferative activity in relation to histology and N-myc amplification in neuroblastoma

    Am J Pathol

    (1990)
  • R. Ladenstein et al.

    Prognostic significance of DNA di-tetraploidy in neuroblastoma

    Med Pediatr Oncol

    (2001)
  • Cited by (31)

    • Calcium signaling regulates fundamental processes involved in Neuroblastoma progression

      2019, Cell Calcium
      Citation Excerpt :

      In addition, there are somatically acquired chromosomal alterations that are frequently associated with advanced stage, high risk NB and poor outcome. These include MYCN gene amplification and segmental chromosomal mutations in 1p, 11q and 17q, as well as other mutations [5,10–12]. The MYCN protein is a basic helix-loop-helix (bHLH) Transcription Factor that is encoded by the MYCN proto-oncogene.

    • Neuroblastoma after Childhood: Prognostic Relevance of Segmental Chromosome Aberrations, ATRX Protein Status, and Immune Cell Infiltration

      2014, Neoplasia (United States)
      Citation Excerpt :

      Patients with a localized stage and NCA tumor remained without recurrence or progression in accordance with results previously described in childhood NB [11]. In childhood NB, homMNA is frequent at a median age of 28 months, and tumors with homMNA appear to have rapid growth [31,33–36]. These facts indicate that homMNA tends to be an early phenomenon in oncogenesis, implying a different route of tumor evolution [11,34,37].

    • Immunohistology of Pediatric Neoplasms

      2011, Diagnostic Immunohistochemistry
    • Immunohistology of Pediatric Neoplasms: Neuroblastoma and Neuroblastic Tumors

      2010, Diagnostic Immunohistochemistry: Theranostic and Genomic Applications, Expert Consult
    • Centrosome amplification is correlated with ploidy divergence, but not with MYCN amplification, in neuroblastoma tumors

      2009, Cancer Genetics and Cytogenetics
      Citation Excerpt :

      These clones served as surrogates for diploidy and triploidy on the basis of correlation of two and three D1Z1 signals with near-diploid (44–57) and near-triploid (58–80) chromosome numbers, respectively, or DNA indexes of 1.0–1.26 and 1.18–1.71, respectively, by flow-cytometry [6,11]. In a recent study on neuroblastoma, Spitz et al. [20] confirmed the validity of using disomy 1 and trisomy 1 as surrogates for diploidy and triploidy, respectively. Thus, tumors were classified into diploid and triploid groups on the basis of the constitution of chromosome 1.

    View all citing articles on Scopus

    Conflict of interest statement: The authors disclose that they have no financial or personal relationships with other people or organizations that could inappropriately influence their work.

    View full text