Objective: To evaluate levels of common specific fusion transcripts M-bcr-abl, m-bcr-abl, TEL-AML1, AML1-ETO, PML-RAR alpha, CBF beta-MYH11 in untreated leukemia patients.
Methods: Specific fusion transcript levels were detected by TaqMan-based real-time quantitative RT-PCR technique in a total of 208 samples, including 195 bone marrow samples from 50 M-bcr-abl(+) chronic phase-chronic myeloid leukemia (CML-CP), 10 M-bcr-abl(+) acute lymphoblastic leukemia (ALL), 19 m-bcr-abl(+) ALL, 11 TEL-AML1(+) ALL, 30 AML1-ETO(+) acute myeloid leukemia (AML), 58 PML-RAR alpha(+) acute promyelocytic leukemia (APL) and 17 CBF beta-MYH11(+) AML patients and 13 peripheral blood samples from 13 M-bcr-abl(+) CML-CP patients. abl was chosen as internal control gene. Fusion transcript level was calculated as fusion transcript copies/abl transcript copies in percentage.
Results: Bone marrow and peripheral blood samples of CML-CP patients had similar M-bcr-abl fusion transcript levels (median 30% vs 35%, P > 0.05). M- and m-bcr-abl (median 64% vs 54%) levels were similar in ALL patients (P > 0.05), M-bcr-abl level was significantly higher in ALL than CML-CP patients(P < 0.001). Median TEL-AML1 level was 228% in ALL patients. Among AML patients, AML1-ETO level was significantly higher than CBF beta-MYH11 and PML-RAR alpha levels (median 388% vs 145%, 388% vs 47%, all P < 0.001), CBF beta-MYH11 level was significantly higher than PML-RAR alpha level (P < 0.001). Fusion transcript levels of L-, V- and S-type PML-RAR alpha were 45%, 44% and 55%, respectively. L-type was significantly lower than S-type (P = 0.04).
Conclusions: Fusion transcript levels in untreated leukemia patients were different and patient-to-patient variations did exist. Detection of fusion transcript levels in untreated leukemia patients not only provides baseline for minimal residual disease monitoring and treatment evaluation but also enable the comparison in inter-laboratory data.