Myeloid Leukemia

Diagnosis of AML1-MTG8 (ETO)-Positive AML 157
Fig. 4. Standard curves for ABL and AML1-MTG8(ETO) prepared with serial dilutions
of constructs for both transcripts.
3.5. Data Analysis and Assessment of Assay Sensitivity/Reliability
The level of fusion transcripts should be assessed by the ratio of the fusion
transcript level to the control transcript level. A number of groups multiply this
ratio by 10 5 , because it is estimated that 1 µg of RNA contains 10 5 copies of
ABL transcript. Recently, and to reduce the confusion of various methods of
presenting quantified levels, many researchers have elected to simply divide
the fusion transcript level by the control transcript level, i.e., AML1-MTG8
(ETO)/ABL ratio (see Fig. 5).
As can be seen from Fig. 5, the relapse risk threshold for BM and PB samples
of t(8;21) AML patients are 0.01 (10 3 /10 5 ABL) and 0.001 (10 2 /10 5 ABL),
respectively. A BM sample with a ratio of 0.01 but an ABL level of