[Detection of core-binding factor in acute leukemia with interphase fluorescence in situ hybridization]

To detect the chromosomal abnormalities involving the core-binding factor (CBF) in acute leukemia at initial diagnosis with interphase in situ hybridization (I-FISH) technique, and monitor the minimal residual disease (MRD) after treatment with I-FISH. This study also aim to compare the sensitivity of I-FISH at initial diagnosis with that of conventional G-banding analysis.

Based on the diagnosis of bone marrow morphology, 15 acute leukemia patients were examined with conventional G-banding and I-FISH techniques. Seven of these patients were monitored for MRD with I-FISH after treatment.

On the basis of the false-positive rate acquired from normal subjects, the normal cutoff values of the 3 probes including AML1/ETO translocation probe, MYH11 breakpoint region probe and ETV6/AML1 translocation probe were 4.13%, 1.95% and 2.12% respectively. With conventional G-banding analysis, 40% (6/15) patients were found with chromosomal abnormality involving CBF, including 5 of the 8 M2 patients with t (8;21) and 1 of the 2 M4EO patients with inv (16). No B-ALL cases were identified with t (12;21). With I-FISH, however, 80% (12/15) of the cases were found with genetic abnormality involving CBF, including all the 8 M2 cases with AML1/ETO fusion gene, both of the M4EO cases with CBFbeta/MYH11 and 2 of the 5 B-ALL cases with ETV6/AML1. In the 7 cases monitored for MRD level with I-FISH, 2 M2 cases and 1 B-ALL case were with positive results.

I-FISH is more sensitive than conventional G-binding analysis in detecting the chromosomal abnormalities involving CBF in acute leukemia. At the time of initial diagnosis, combination of the two techniques may lead to more comprehensive and accurate results.