Quantitative real-time polymerase chain reaction (PCR) is used to detect the t(9;22) BCR-ABL1 fusion transcripts that result in major (p210), minor (p190), and/or micro (p230) fusion proteins. Minimal residual disease monitoring results for the major breakpoint transcripts are reported and graphed on the International Scale (IS). Monitoring results for the minor breakpoints transcripts are reported.
The BCR-ABL1 fusion gene is the hallmark finding in BCR-ABL1-positive chronic myelogenous leukemia (CML), but it can also be found in other hematologic neoplasms, including 25-30% of adult B-cell acute lymphoblastic leukemia (B-ALL), 3-5% of pediatric B-ALL, and rarely in acute myeloid leukemia (AML) and T-cell acute lymphoblastic leukemia (T-ALL). The major (p210) breakpoint transcript is the most common type found in CML, but minor (p190) breakpoint transcripts can also be found in rare cases of CML with atypical phenotype features. The minor (p190) breakpoint transcript is associated with increased monocytes. The p230 contains additional BCR coding sequences that are not found in the p190 or p210 variants. The course of CML in patients with p230 is milder than that in average CML. Monitoring treatment response to tyrosine kinase inhibitor (TKI) therapy is crucial in the management of patients with CML to assess response and detect resistance. Guidelines currently recommend monitoring response to TKI therapy by quantitative PCR using the International Scale (IS).
- Bone Marrow: 2-3 mL in EDTA tube
- Peripheral Blood: 2-3 mL in EDTA tube
Use cold pack for transport, making sure cold pack is not in direct contact with specimen. DO NOT FREEZE.