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Distinct genetic patterns can be identified in acute monoblastic and acute monocytic leukaemia (FAB AML M5a and M5b): a study of 124 patients
Author(s) -
Haferlach Torsten,
Schoch Claudia,
Schnittger Susanne,
Kern Wolfgang,
Löffler Helmut,
Hiddemann Wolfgang
Publication year - 2002
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1046/j.1365-2141.2002.03599.x
Subject(s) - medicine , biology , oncology
Summary. The French–American–British (FAB) classification and the new World Health Organization (WHO) classification distinguish acute monoblastic leukaemia (AML M5a) from acute monocytic leukaemia (AML M5b). Not much is known about the underlying genetic differences leading to these clearly different phenotypes. We analysed 58 patients with de novo AML M5a and 66 patients with denovo AML M5b in comparison with a whole group of 1603 de novo AML. An aberrant karyotype was found in 75·9% of AML M5a but in only 28·8% of M5b ( P < 0·0001) and in 54·7% of all other AML subtypes ( P = 0·0015). 11q23/MLL aberrations were detected in 31% of M5a, 12·1% of M5b ( P = 0·01) but only 1·3% of all other AML subtypes ( P < 0·0001). Trisomy 8 as the sole cytogenetic aberration was found in 22·4% of M5a, but in only 3% of M5b and in 2·5% of all other AML subcategories ( P < 0·0001). Although the frequency of the MLL‐partial tandem duplication (MLL‐PTD) did not differ between the three cohorts (1·7%, 4·5% and 6·1% respectively, NS), thedetection of FLT3 length mutations (FLT3‐LM) differed significantly. AML M5a showed a low frequency of only 6·9%, but 28·8% of M5b ( P = 0·0014) and 23·5% of all other AML revealed a FLT3‐LM. In conclusion, we demonstrated genetic, i.e. biological, differences between AML M5a and AML M5b and all other AML. Therefore, AML M5 should further be categorized as two different groups, as proposed by the WHO classification.