1. ¹Departments of Cytogenetic and Cytologic, Hôpital Robert Debré, Reims, France
2. ²Departments of Cytogenetic and Cytologic, Hôpital Jeanne de Flandre, Lille, France
3. ³Departments of Cytogenetic and Cytologic, Hôpital Bretonneau, Tours, France
4. ⁴Departments of Cytogenetic and Cytologic, CHU, Angers, France
5. ⁵Departments of Cytogenetic and Cytologic, Hôpital Kremlin-Bicêtre, Kremlin-Bicêtre, France
6. ⁶Departments of Cytogenetic and Cytologic, Hôpital Haut-Levêque, Bordeaux, France
7. ⁷Departments of Cytogenetic and Cytologic, Hôpital de Hautepierre, Strasbourg, France
8. ⁸Departments of Cytogenetic and Cytologic, Hôpital Hôtel-Dieu, Nantes, France
9. ⁹Departments of Cytogenetic and Cytologic, Hôpital St-Antoine, Paris, France
10. ¹⁰Departments of Cytogenetic and Cytologic, Hôpital Nord, Saint-Etienne, France
11. ¹¹Departments of Cytogenetic and Cytologic, Institut Paoli-Calmettes and Université de la Méditerranée, Marseille, France
12. ¹²Departments of Cytogenetic and Cytologic, Hôpital Avicenne, Bobigny, France
13. ¹³Departments of Cytogenetic and Cytologic, Hôpital du Bocage, Dijon, France
14. ¹⁴Departments of Cytogenetic and Cytologic, CHU, Grenoble, France
15. ¹⁵Departments of Cytogenetic and Cytologic, CHU, Liège, Belgium
16. ¹⁶Departments of Cytogenetic and Cytologic, Ghent University Hospital, Ghent, Belgium
17. ¹⁷Departments of Cytogenetic and Cytologic, Cliniques Universitaires St-Luc-UCL, Bruxelles, Belgium
18. ¹⁸Departments of Cytogenetic and Cytologic, CH Lyon Sud, Lyon, France
19. ¹⁹Departments of Cytogenetic and Cytologic, Hôpitaux Universitaires, Genève, Switzerland
20. ²⁰Departments of Cytogenetic and Cytologic, Hôpital André Mignot, Versailles, France
21. ²¹Departments of Cytologic, Hôpital Henri Mondor, Créteil, France
22. ²²Departments of Cytogenetic and Cytologic, Hôpital Necker Enfants Malades, Paris, France

Correspondence: Dr C Terre, Laboratoire de cytogénétique, Hôpital André Mignot, 177, rue de Versailles, Le Chesnay 78 150, France. E-mail: cterre@ch-versailles.fr

Received 31 May 2007; Revised 9 August 2007; Accepted 13 August 2007; Published online 11 October 2007.

Abstract

A series of 38 patients with acute myeloblastic leukemia (AML) with 49 or more chromosomes and without structural abnormalities was selected within the Groupe Francophone de Cytogénétique Hématologique (GFCH) to better define their characteristics. The median age of the patients was 65 years, and all FAB subtypes were represented. Although all chromosomes were gained, some seems to prevail: chromosome 8 (68%), 21 (47%), 19 (37%), and 13 and 14 (34% each). Since MLL rearrangement leads patients in a group with an unfavorable prognosis, search for cryptic rearrangements of MLL was performed in 34 patients and showed abnormalities in 5 (15%). When we applied the most frequent definition of complex karyotypes (three or more abnormalities), all patients with high hyperdiploid AML fall in the unfavorable category. Among the 18 patients without MLL rearrangement receiving an induction therapy, 16 (89%) reached CR and 6 (33%) were still alive after a 31-month median follow-up (14–61 months). Although this study was retrospective, these results suggest that high hyperdiploid AML without chromosome rearrangement seems to be a subgroup of uncommon AML (less than 1%), and may be better classified in the intermediate prognostic group.