1. ¹INSERM, U830, Section de Recherche, Unité de Génétique et Biologie des Cancers, Institut Curie, Paris, France
2. ²Institut Curie, Unité de Génétique Somatique, Paris, France
3. ³Université Paris7, EA3102, AP-HP Hôpital R Debré, Service de Pathologie, Paris, France
4. ⁴Institut Curie, Unité de Cytogénétique, Paris, France

Correspondence: Dr O Delattre, Section de Recherche, INSERM U830, Unité de Génétique et Biologie des Cancers, Institut Curie, 26, rue d'Ulm, Paris Cedex 05 75248, France. E-mail: olivier.delattre@curie.fr

Received 31 May 2007; Revised 22 October 2007; Accepted 25 October 2007; Published online 10 December 2007.

Abstract

Neuroblastic tumours are composed of variable proportions of neuroblasts and Schwann cells. Whether both components share a common neoplastic origin is highly debated and discrepant results have been reported about the presence of tumour-related genetic alterations in Schwann cells. We have used X-methylation analysis and array-CGH to investigate contiguous Schwannian and neuroblastic areas in tumours with a nodular pattern. A skewed X inactivation was observed in four out of five stromal components. Interestingly, in these four cases, the X-inactivation profiles of the neuroblastic components were identical to the matched stromal areas. However, whereas all neuroblastic areas displayed chromosomal imbalances, no alteration was found in any Schwann cell components. Similarly, no alteration was observed in a series of 19 tumours with a single stroma-rich component, which occasionally exhibited a skewed X-inactivation pattern (3/17 informative tumours). Altogether, this indicates that most stroma-rich tumours display a polyclonal proliferation and that Schwann cells do not derive from neuroblasts. However, in tumours with both stroma-rich and -poor components, our results suggest that cells from both areas share a common progenitor.