THE EXPRESSION OF MULTIDRUG
RESISTANCE GENE IN ALL-MRD
Zhao HN, Bai XL, Chen
J, Guo JH
Jinan Military
General Hospital, Jinan, China
Objective: To
probe into the relation of acute lymphoblastic leukemia-minimal residual
disease (ALL-MRD) to the expression of tumor's multidrug resistance gene
(mdr1-mRNA).
Methods: The
fragments of TCRγ
monoclonal gene rearrengements were amplified by PCR so that MRD was
determined. At the same time, the mdr1-mRNA expression of the same samples
was detected by RT-PCR. Electrophoresis gel with the specific positive
bands was quantitated by GQS-960 image processing system software,
calculating the values of mdr1/β2-MG
and defining the values which were ≥0.3
as positive expression.
Results:
(1)The positive detective rates of TCRγ
monoclonal gene re-arrengements were 81.8% in the cases with ALL before
chemotherapy. The complete remission （CR） rates were 90.9% (30/33)
and the positive rates of MRD were 80.0% (24/30) at CR. (2) The positive
rates of MRD fell gradually during the following-up observation lasting 6
to 18 months, while the positive expression rates of mdr1-mRNA were rising
gradually. (3)The relapse frequencies of ALL were 71.4% (5/7) in MRD+＋mdr1+ group, 0% (0/9) in
MRD-＋mdr1- group, and 25.5% in
MRD+＋mdr1- group and MRD-＋mdr1+ group.
Conclusion:
(1) The positive rates of MRD were down gradually with long-time CR and by
conducting intensified chemotherapy on schedule after ALL-CR, while the
positive expression rates of mdr1-mRNA were up gradually. The two rates
were of negative correlation. (2) The relapse frequencies were high in the
cases in which both MRD and mdr1-mRNA were positive, pointing out the poor
prognosis. (3) Monitoring MRD and mdr1 on schedule during CR can provide
scientific basis for clinical individualization of chemotherapy plan to
eliminate MRLC thoroughly.