Differentiation of acute myeloid leukemia from B- and T-lineage acute lymphoid leukemias by real-time quantitative reverse transcription-PCR of lineage marker mRNAs.
BACKGROUND
Flow cytometry of lineage markers is useful in the classification of leukemias. Our aim was to assess whether the study of lineage genes at the RNA level would enable differentiation of acute myeloid leukemias (AMLs) from B-and T-lineage acute lymphoid leukemias (ALLs).


METHODS
We measured mRNA of four lineage markers [CD19, CD79a, CD3e, and myeloperoxidase (MPO)] by reverse transcription followed by real-time quantitative (RTQ)-PCR. We investigated 72 acute leukemias (40 AMLs with 23-93% blast cells plus 27 B-lineage ALLs and 5 T-lineage ALLs) defined by morphologic criteria at diagnosis. RTQ-PCR analysis was performed on bone marrow without cell sorting. The expression of each gene was calculated as the difference in the threshold cycle [DeltaCT; CT value of target gene minus CT value of housekeeping gene (Abelson)].


RESULTS
Three patterns of expression were detected. In the first, CD19, CD79a, and MPO mRNAs were less abundant than CD3e. In the second pattern, MPO mRNA was more abundant than the other three mRNAs. In the third, CD19 or CD79a was more highly expressed than CD3e and MPO. The three patterns corresponded to T-ALL, AML, and B-ALL, respectively. The use of cutoffs to establish qualitatively the pattern of coexpression of the four lineage markers provided the same information as the comparison among the four DeltaCT values. Prospective use of the scoring system correctly classified each of 13 additional cases (8 AML, 4 B-lineage ALL, and 1 T-lineage ALL).


CONCLUSIONS
Study of lineage markers at diagnosis by RTQ-PCR allows differentiation of AML from B-ALL or T-ALL without cell sorting, even when the bone marrow contains few blast cells.
Saussoy
Pascale
P
Cliniques Universitaires Saint Luc, Service de Biologie Hématologique, Brussels, Belgium. Saussoy@sang.ucl.ac.be
Vaerman
Jean-Luc
JL
Straetmans
Nicole
N
Deneys
Véronique
V
Cornu
Guy
G
Ferrant
Augustin
A
Latinne
Dominique
D
D000328:Adult; D015703:Antigens, CD / Q000032:analysis / Q000235:genetics; D018941:Antigens, CD19 / Q000032:analysis / Q000235:genetics; D015415:Biomarkers / Q000032:analysis; D001853:Bone Marrow / Q000737:chemistry; D002051:Burkitt Lymphoma / Q000145:classification / Q000175:diagnosis*; D017252:CD3 Complex / Q000032:analysis / Q000235:genetics; D051925:CD79 Antigens; D019070:Cell Lineage; D002648:Child; D003937:Diagnosis, Differential; D006801:Humans; D016130:Immunophenotyping; D015470:Leukemia, Myeloid, Acute / Q000145:classification / Q000175:diagnosis*; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000145:classification / Q000175:diagnosis*; D009195:Peroxidase / Q000032:analysis / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis*; D011947:Receptors, Antigen, B-Cell / Q000032:analysis / Q000235:genetics; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction
D015703:Antigens, CD; D018941:Antigens, CD19; D015415:Biomarkers; D017252:CD3 Complex; C115335:CD3E protein, human; D051925:CD79 Antigens; C497881:CD79A protein, human; D012333:RNA, Messenger; D011947:Receptors, Antigen, B-Cell; D009195:Peroxidase