Representative patterns of residual disease found in IM-treated patients achieving CMR. Panels A and B show 2 individual patients. On the x-axis are months on imatinib (IM). The results of the quantitation of BCR-ABL transcripts (■) are expressed as the ratio of BCR-ABL to ABL mRNA (y-axis, in a logarithmic scale). The results of the real-time quantitative polymerase chain reaction for gBCR-ABL are represented as diamonds: ♦, gBCR-ABL–positive; ◆, gBCR-ABL–negative. (A) gBCR-ABL was initially detected in transcript-negative samples but became undetectable with continuing IM therapy. A similar pattern was seen in 3 other patients tested. (B) The single patient, of 5 tested, in which all transcript-negative samples tested were gBCR-ABL–positive.