MBN expression after initiation of imatinib therapy.

(A) A cDNA-array plot. A patient's mRNA before, as well as 3 and 98 days after, initiation of imatinib therapy was isolated, reverse transcribed, radiolabeled, and then used to probe Atlas 1.2 human cDNA arrays. Arrows indicate the dot location at which theMBN-specific DNA was deposited on the array membrane. The intensity of the signal dots corresponds with expression levels in the tested sample. Plots are representative of arrays on 2 individual CML patients treated with imatinib. A comparable loss of the MBN spot intensity was seen in both tested patients. (B) Regulation of MBN transcript levels under imatinib therapy as assessed by reverse transcriptase–PCR (RT-PCR). RNA was isolated from 5 patients in chronic phase of CML at diagnosis and at 4 and 12 weeks after start of imatinib therapy. At this time, at least a complete hematological remission was achieved. Lower panel: β-actin PCR was used to assess equal loading and integrity of RNA.