[Significance of dynamic detection of WT1 expression on monitoring minimal residual disease in leukemia patients following allogeneic bone marrow transplantation].
OBJECTIVE
To investigate the significance of monitoring Wilms' tumor gene (WT1) expression level in bone marrow of leukemia patients following allogeneic bone marrow transplantation (allo-BMT).


METHODS
Real-time quantitative reverse transcription polymerase chain reaction method was established for measuring WT1 and GAPDH expression levels in bone marrow cells of 15 patients with leukemia, including a total of 111 specimens during the follow-up, and in 23 non-leukemia patients by using LightCycler. Normalized WT1 expression level (WT1(N)) was determined as a ratio of WT1 to GAPDH times 10(4).


RESULTS
The median expression levels of WT1(N) in 17 samples of newly diagnosed patients, 6 samples of relapsed patients, 88 samples from leukemia patient in complete remission and 23 samples of non-leukemic controls were 40.18 (5.48 to 510.27), 125.89 (34.50 to 273.95), 4.80 (0 to 56.96) and 1.47 (0 to 8.56) respectively. Nonparameter statistic analysis (Mann-Whitney U test) showed that the WT1(N) expression levels in the newly diagnosed group and relapsed group were statistically higher than in those in the complete remission group and non-leukemic controls (all P < 0.01), without significant differences between the complete remission group and control group (P = 0.692) and between the newly diagnosed group and relapsed group (P = 0.595). In general, the dynamic curves of WT1(N) levels following allo-BMT were consistent with the tendency of changes in expression levels of corresponding fusion genes for minimal residual disease (MRD) monitoring. Spearman Rho correlation analysis revealed that the correlation coefficient between the WT1(N) expression levels and BCR/ABL, AML/ETO, PML/RARalpha and MLL/AF17 fusion genes expression were 0.678 (P = 0.00), 0.677 (P = 0.00), 0.806 (P = 0.00) and 0.553 (P = 0.049) respectively. Three patients relapsed after allo-BMT and one patient relapsed before allo-BMT during the follow-up. A re-increment of WT1(N) expression level during follow-up could be detected 40 to 180 days earlier to hematological relapse.


CONCLUSIONS
The WT1 expression level of leukemia patients following allo-BMT measured by real time RT-PCR can be a useful tool for monitoring MRD and warning the clinical relapse during follow-up.
Gu
Wei-Ying
WY
The First Affiliated Hospital of Soochow University, Jiangsu Institute of Hematology, Suzhou 215006, China.
Chen
Zi-Xing
ZX
Hu
Shao-Yan
SY
Zhu
Jiang
J
Wang
Zhi-Lin
ZL
Yan
Feng
F
Wang
Wei
W
Cen
Jian-Nong
JN
Shen
Hui-Ling
HL
Qian
Jun
J
D000293:Adolescent; D000328:Adult; D016026:Bone Marrow Transplantation; D002648:Child; D005260:Female; D006801:Humans; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000378:metabolism* / Q000601:surgery; D015470:Leukemia, Myeloid, Acute / Q000378:metabolism* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014184:Transplantation, Homologous; D025721:WT1 Proteins / Q000096:biosynthesis* / Q000235:genetics
D025721:WT1 Proteins