Medknow Publications on behalf of Indian Cancer Society
Abstract
Background: Patients with a presence of Promyelocytic Leukemia-Retinoic
Acid Receptor Alpha (PML-RARA) genes rearrangement predict a favorable
response to all-trans retinoic acid (ATRA), and a significant
improvement in survival. Therefore, establishing the presence of
PML-RARA rearrangement is important for optimal patient management.
Aim: The objective of this study is to compare and assess the role of
fluorescent in situ hybridization (FISH) and reverse transcriptase
polymerase chain reaction (RT-PCR) in the diagnosis and long-term
monitoring of Acute Promyelocytic Leukemia (APL). Materials and
Methods: We compared 145 samples received at different interval of
times to analyze the sensitivity of RT-PCR and FISH. Results: The
failure rate for RT-PCR was 4% at baseline, 13% at induction, and 0% at
the end of consolidation. And for FISH it was 8% at baseline, 38% at
induction, and 66% at the end of consolidation. The predictive values
of relapse in the patients who were positive and negative by RT-PCR, at
the end of induction, were 60 % and 3%, respectively, and at end of
consolidation it was 67 % and 4%, respectively. On the other hand the
predictive values of relapse in patients who were positive and negative
by FISH at end of induction were 57 % and 6%, respectively; while at
end of consolidation it was 14% who were negative by FISH. Conclusion:
Both RT-PCR and FISH are important for the diagnosis of APL cases, as
both techniques complement each other in the absence or failure of any
one of them. However, RT-PCR is more sensitive than FISH for the
detection of minimal residual disease in the long-term monitoring of
these patients. The present study shows that the predictive value of
relapse is more associated with minimal residual disease (MRD) results
by RT-PCR than that by FISH