Retrospective comparison of qualitative and quantitative reverse transcriptase polymerase chain reaction in diagnosing and monitoring the ALL1-AF4 fusion transcript in patients with acute lymphoblastic leukaemia.
We compared quantitative reverse transcriptase polymerase chain reaction (Q-RT-PCR) to qualitative RT-PCR in determining response to therapy and predicting clinical outcome in 18 retrospectively selected patients with ALL positive for the ALL1-AF4 fusion and with frozen RNA samples collected at diagnosis and during follow-up (96 samples analysed). The ALL1-AF4 junction was detected by qualitative RT-PCR in 18 patients and by Q-RT-PCR in 17 patients (one patient harboured the rare e10-e6 ALL1-AF4 junction, which falls outside of the primer and probe location designed for the Q-RT-PCR). In three of the 12 patients negative to qualitative RT-PCR after induction therapy, a small number of ALL1-AF4 copies was detected by Q-RT-PCR. Thus nine patients were negative and eight positive. Seven of the eight positive patients suffered a relapse, including two of the three patients positive to Q-RT-PCR yet negative to qualitative RT-PCR. Moreover, we found two (5%) discordant results among the 39 follow-up tests of the nine patients who converted to a negative qualitative-quantitative PCR status. The results suggest that qualitative RT-PCR is more appropriate for the routine diagnosis of this genetic alteration. However, Q-RT-PCR is more accurate in assessing the molecular response after induction treatment and could be more useful in clinical decision-making in ALL1-AF4-positive ALL patients.
Department of Cellular Biotechnology and Haematology, La Sapienza University, Rome, Italy.
L
L
Elia
E
E
Gottardi
G
G
Floriddia
R
R
Grillo
F
F
Ciambelli
M
M
Luciani
P
P
Chiusolo
R
R
Invernizzi
G
G
Meloni
R
R
Foà
G
G
Saglio
G
G
Cimino
D000293:Adolescent; D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001483:Base Sequence; D016026:Bone Marrow Transplantation; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D008991:Monitoring, Physiologic; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics* / Q000628:therapy*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D012074:Remission Induction; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012689:Sequence Homology, Nucleic Acid
C403194:ALL1-AF4 fusion protein, human; D015514:Oncogene Proteins, Fusion; D012333:RNA, Messenger; D012334:RNA, Neoplasm