Discussion

The present study differs from previous studies in that the normal control, for setting the reference range for the PML/RARA and RARA signals, included non-APL patients (14 cases) with hematological malignancies at the time of follow-up after chemotherapy, rather than normal individuals. We attempted to determine whether the alignment of chromosomes in the interphase after chemotherapy could affect the interpretation of FISH. Almost no difference was found in the reference ranges for PML/RARA between 20 specimens of normal bone marrow and 14 specimens of the bone marrow of non-APL patients at follow-up (p value=0.17, Student's t test). However, a difference was found in the cutoff values between 30 specimens of peripheral blood (5.47%) and 20 specimens of normal bone marrow (6.21%). The results of normal bone marrow were higher than those of peripheral blood, although the difference was not significant statistically (p value=0.59, Student's t test).

If a normal cutoff of 5% for PML/RARA FISH is applied, which is the same as the remission criterion (5%) by morphology, conducting FISH will not give any additional information. From the aspect of minimal residual disease detection, RARA FISH with a lower reference range of 1.5% would be more informative. Although the reference range of FISH does not usually matter in making a decision about APL at initial diagnosis, this range could significantly affect the clinical determination of complete remission during the treatment of APL, as positive RT-PCR results are frequently obtained after induction therapy, irrespective of the achievement of remission.

According to the results of the present study, the advantages of performing RARA FISH are that 1) false positivity due to the design problem of PML/RARA FISH can be reduced; 2) accurate quantitative results can be obtained; and 3) the interpretation difficulty experienced when the result is around the normal reference range with PML/RARA FISH can be resolved by RARA FISH. Thus at the time of follow-up of APL, employing RARA FISH would be more effective. Nevertheless, as it is important to determine the presence or absence of t(15;17) in the diagnosis of APL, PML/RARA FISH or PML/RARA RT-PCR needs to be considered at the time of initial diagnosis, and when their result is positive, we recommend performing RARA FISH, not PML/RARA FISH, during follow-up. On the other hand, in those cases that are difficult to interpret, because the PML/RARA FISH results are around the reference range, we believe that RARA FISH helps in the interpretation. We also recommend examining quantitative changes through repeated follow-up tests in each case during follow-up, rather than giving significance to only one test.

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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