Poster Presentation Advances in Neuroblastoma Research Congress 2016

Composite Neuroblastoma: Unique tumours with morphologically and genetically defined intratumoral heterogeneity (#259)

Hervé Sartelet 1 , Alexander Valent 2 , Gabriele Amann 3 , Klaus Beiske 4 , Catherine Cullinane 5 , Emanuele D'amore 6 , Claudio Gambini 7 , Jason Jarzembowski 8 , Vijay Joshi 9 , Ivo Leuschner 10 , Samuel Navarro 11 , Hajime Okita 12 , Angela Samenta 7 , Larry Wang 13 , Hiroyuki Shimada 13 , Michel Peuchmaur 14
  1. CHU Grenoble, Grenoble, France
  2. Institut Gustave Roussy, Villejuif, France
  3. INPC Committee, Wien, austria
  4. INPC Committee, Oslo, Norway
  5. INPC committee, Leeds, UK
  6. INPC Committee, Padova, Italy
  7. INPC Committee, Genova, Italy
  8. INPC Committee, Milwaukee, USA
  9. INPC Committee, Hartford, USA
  10. INPC committee, Kiel, Germany
  11. INPC Committee, Valencia, Spain
  12. INPC Committee, Tokyo, Japan
  13. INPC Committee, Los Angeles, USA
  14. INPC Committee, Paris , France

Background. Peripheral neuroblastic tumours make one of the most common paediatric neoplasms, and are characterized by clinical and biological heterogeneity. Intratumoral heterogeneity is well documented in Ganglioneuroblastoma, nodular (composite, Schwannian stroma-dominant/stroma-rich and stroma-poor) category. However little is known about “Composite Neuroblastoma” with intratumoral heterogeneity in Neuroblastoma (Schwannian stroma-poor) category.

Methods. First, a series of 12 neuroblastomas showing morphological heterogeneity were identified by the International Neuroblastoma Pathology Committee. All of those tumours were composed of 2 clearly distinct histology areas: i.e., 2 different components based on the grade of neuroblastic differentiation and/or mitosis-karyorrhexis-index. Then genetic intratumoral heterogeneity was analyzed by the fluorescence in situ hybridization (FISH) method using the formalin-fixed and paraffin-embedded sections from each of 24 distinct components of those tumours.   FISH performed in this study tested (1) MYCN genomic status using a MYCN probe in 2p24 and a reference DNA probe Laf (2q11), and (2) Gene rearrangements (gain) using a Dual Fusion Probe containing a mixture of two probes for PML gene (15q22) and RARA gene (17q21.1).

Results. The first FISH analysis with MYCN and Laf probes demonstrated genetic difference between the two morphologically distinct components for 10 of 12 cases: namely one component showed disomy and the other had polysomy/gain. None of 24 components in this series had amplified MYCN defined by the presence of MYCN signals more than 4 times reference signals. The second FISH analysis also demonstrated difference of 17q21.1 status (disomy vs. gain) between the two components for 11 of 12 cases. Overall, the two morphologically distinct areas (components) of all the 12 tumours demonstrated different genetic characteristics by the FISH tests.

Conclusion. This study verified the intratumoral heterogeneity; i.e., presence of different clones, in “Composite Neuroblastoma”.   Those different clones in the individual tumours were first identified morphologically and then completely confirmed genetically.