Table 2.
Scoring molecular response.
| Type of Response | BCR-ABL1 Levels a | Reduction in BCR-ABL1 Transcript Levels b | Sum of Reference Gene Transcripts c |
|---|---|---|---|
| CCyR d | ≤1% | ≥2 log | ≥10,000 ABL1 i or 24,000 GUSB j |
| MMR or MR3 e | ≤0.1% | ≥3 log | ≥10,000 ABL1 or 24,000 GUSB |
| MR4 f | ≤0.01% | ≥4 log | ≥10,000 ABL1 or 24,000 GUSB |
| MR4.5 g | ≤0.0032% | ≥4.5 log | ≥32,000 ABL1 or 77,000 GUSB |
| MR5 h | ≤0.001% | ≥5 log | ≥100,000 ABL1 or 240,000 GUSB |
a on the International Scale (IS) [18] b from IRIS baseline representing the median value of BCR-ABL1/BCR present at diagnosis [44] c numbers of ABL1 transcripts in the same volume of cDNA used to test for BCR-ABL1 d CCyR—complete cytogenetic remission, e MMR/MR3—major molecular response, f MR4—undetectable disease in cDNA with >10,000 ABL1 transcripts, g MR4,5—undetectable disease in cDNA with >32,000 ABL1 transcripts, h MR5—undetectable disease in cDNA with >100,000 ABL1 transcripts, i minimal sensitivity for accurate quantification [49], j GUSB—beta glucuronidase.