Comparison of FISH and quantitative RT-PCR for the diagnosis and follow-up of BCR-ABL-positive leukemias.
BACKGROUND
For Philadelphia chromosome positive (Ph+) leukemias (chronic myelogenous leukemia [CML], acute lymphoblastic leukemia [ALL], and rare other leukemias), both allogeneic transplantation and treatment with tyrosine kinase inhibitors offer chances of molecular remission (the molecular marker being consistently undetectable). Molecular remission is defined as a reduction in the quantification of BCR-ABL transcripts to an undetectable level by molecular diagnostic methods, and is considered as a surrogate marker for cure or long-term disease control. The molecular diagnostic methods including fluorescence in situ hybridization (FISH) and quantitative reverse transcription-polymerase chain reaction (QRT-PCR) are more sensitive than classical cytogenetic analysis for the detection of BCR-ABL positive cells. QRT-PCR, due to its superior sensitivity, is considered the gold standard for the follow-up of Ph+ leukemias treated with imatinib.


OBJECTIVE
The objective of our study was to compare the diagnostic and clinical usefulness of FISH and QRT-PCR at different timepoints for Ph+ leukemias.


METHODS
We investigated 23 unselected patients with Ph+ CML (n = 21) or Ph+ ALL (n = 2) at 77 different timepoints in a comparative study with both FISH and QRT-PCR using commercially available reagents in a routine laboratory.


RESULTS
Our study demonstrated a good correlation of QRT-PCR with FISH in detecting the BCR-ABL fusion gene among patients with CML or ALL (coefficient of correlation = 0.77493, p < 0.0001, using Spearman's correlation procedure). All newly diagnosed or untreated cases were positive with both methods. Lower coefficients of correlation were found when FISH and QRT-PCR were correlated with the white blood cell count (WBC). An overall concordance of FISH and QRT-PCR (being either negative or positive in both tests) was found in 65 cases (84.4%) and a discrepancy identified in 12 cases (15.6%).


CONCLUSIONS
We confirm that QRT-PCR allows precise measurement of low levels of BCR-ABL transcripts and can serve as a sensitive indicator for minimal residual disease. In addition, we demonstrate in most cases a good correlation of QRT-PCR with FISH in detecting the BCR-ABL fusion gene among patients with CML or Ph+ ALL. FISH is not suitable for monitoring minimal residual disease.
Bao
Fei
F
Department of Pathology, Louisiana State University, Shreveport, Louisiana, USA.
Munker
Reinhold
R
Lowery
Clarissa
C
Martin
Sherry
S
Shi
Runhua
R
Veillon
Diana M
DM
Cotelingam
James D
JD
Nordberg
Mary Lowery
ML
D000328:Adult; D000368:Aged; D001772:Blood Cell Count; D005260:Female; D005500:Follow-Up Studies; D016044:Fusion Proteins, bcr-abl / Q000378:metabolism*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D007938:Leukemia / Q000097:blood / Q000175:diagnosis* / Q000378:metabolism*; D007962:Leukocytes; D008297:Male; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*
D016044:Fusion Proteins, bcr-abl
Haematologica. 2006 Apr;91(4):513-21
16533723
Leuk Lymphoma. 2006 Mar;47(3):397-402
16396761
Leuk Res. 2007 Apr;31(4):483-91
16945414
Blood Rev. 2006 Jan;20(1):29-41
16426942
Curr Opin Hematol. 2005 Jan;12(1):33-9
15604889
Semin Hematol. 2001 Jul;38(3 Suppl 8):22-7
11526598
Blood. 2005 Apr 1;105(7):2640-53
15618470
J Exp Clin Cancer Res. 2004 Jun;23(2):295-9
15354415
N Engl J Med. 1999 Apr 29;340(17):1330-40
10219069
Ann Oncol. 2006 Mar;17(3):495-502
16403813
Br J Haematol. 1998 Jun;101(3):552-7
9633901
Leukemia. 2002 Jan;16(1):53-9
11840263
Clin Cancer Res. 2005 May 1;11(9):3425-32
15867244
Eur J Haematol. 2004 Oct;73(4):243-50
15347310
Hematology Am Soc Hematol Educ Program. 2006;:211-8
17124063
Curr Opin Hematol. 2003 Jul;10(4):284-9
12799534
Eur J Haematol. 2002 May;68(5):272-80
12144533
Blood. 2000 Jan 15;95(2):404-8
10627442
Blood. 2003 Jun 15;101(12):4701-7
12576334