AML with 11q23/MLL Abnormalities: A Survey of 146 Cases from French AML Intergroup.

Karyotype is one of the most important prognosis factor in acute myeloid leukemia. The MLL gene, located at 11q23, is fused to a variety of partner genes through chromosomal translocations and generates the critical leukemogenic fusion proteins. We performed a large retrospective study in 146 adults and children with 11q23/MLL + rearrangement enrolled in 6 clinical trials conducted in France between 1987 and 1998. Prognosis studies were performed in the 110 patients (47 adults and 63 children) who achieved a complete remission. Individual data were registred, including age, blood and marrow count, extramedullary disease and cytogenetics. The kaplan-Meier method was used in survival analysis and the cox proportinal-hazards model was used to analyse the effect of potential prognosis factors on survival. Among 47 adults, 43 % (20/47) carried t(9 ;11), 19% (9/47) carried t(6 ;11), 23% (11/47) carried t(11 ;19), 6% (3/47) carried t(10 ;11) and 8% (4/47) carried another abnormalities involved 11q23/MLL. Estimated 5-year disease-free survival (DFS), overall survival (OS) and relapse rate (RR) were respectively 17%, 21% and 77%. We analysed separately all translocations involved MLL and we found that the only translocation indicating a favorable prognosis was the translocation t(11 ;19). Compared with other translocations involving MLL, the estimated 5-year DFS, OS and RR of patients with a t(11 ;19) were respectively 45 vs 8% (p=.02), 54 vs 11% (p=.006) and 48 vs 84% (p=.04). Relative risk of relapse was 0,29 (95% confidence interval, 0.09 to 0,9 ;p=.03). Among 63 children, 63% (40/63) carried t(9 ;11), 3% (2/63) carried t(6 ;11), 8% (5/63) carried t(11 ;19), 14% (9/63) carried t(10 ;11) and 11% (7/63) carried another MLL rearrangement. Estimated 5-year DFS, OS and RR were respectively 59%, 72% and 36%. Compared with other translocations involving MLL, we found no difference in outcome between patients with t(9 ;11) and those with other rearrangement of MLL. In conclusion, the most common recurrent abnormality in this large study was translocation t(9 ;11) in adults and children. We found that adults patients whose leukemic cells contained the t(11 ;19) have a better outcome compared with those whose leukemic cells contain other 11q23 /MLL alterations. In children, we do not confirm the favorable impact of t(9 ;11) suggested in previous reports.