MOLECULAR ANALYSIS OF MINIMALLY DIFFERENTIATED ACUTE MYELOID-LEUKEMIAWITH CHROMOSOME-16 INVERSION

We report a 3-year-old girl with minimally differentiated acute myeloi d leukemia and chromosome 16 inversion (inv 16). Inv 16 is generally a ssociated with acute myelomonocytic leukemia with dysplastic eosinophi ls in the bone marrow (AML-M4Eo). Recently, molecular analysis showed that a fusion gene is generated by this inversion between the CBFB gen e on the q arm and the MYH11 gene on the p arm. Using reverse transcri ptase-polymerase chain reaction analysis, we tried to detect CBFB/MYH1 1 chimeric mRNA in blasts from our patient, however, were unable to de tect any chimeric mRNA in the blasts. The absence of CBFB/MYH11 transc ripts in this case suggests that rare chimeric products might be forme d as a result of inv 16 that could not be detected by the primer sets used in this study. Another possibility is that different genes are re arranged on the chromosome 16 with the inv 16. More detailed molecular analysis of this case might be necessary in order to elucidate these possibility. Analyzing leukemias with inv 16 which do not have a typic al CBFB/MYH11 chimeric mRNA might lead to understanding an alternative pathogenesis for acute leukemia with inv 16.