Real-time RT-PCR for detection of t(9;22) BCR-ABL1 fusion transcripts that result in p230 (e19a2) fusion proteins. Analytical sensitivity is 1 tumor cell in 100,000 normal cells. Results are reported as percent abnormal. Test can be ordered as a reflex when BCR-ABL1 Standard p210, p190 is negative.
Subsets of patients with Ph1+ chronic myeloid leukemia (CML) have a unique breakpoint within the BCR gene on chromosome 22. This breakpoint is 3’ to the more common breakpoints found in patients with CML and ALL and can lead to e19a2 fusion transcript. Thus, p230 BCR-ABL1 contains additional BCR coding sequences that are not found in the p190 or p210 variants. The incidence of this translocation is very rare, but may lead to falsely negative molecular testing when the molecular testing is designed to detect breakpoints in E1, E13 or E14. Although some studies suggested that the course of CML in patients with p230 is milder than that in average CML, response to therapy is similar. However, very little literature is available due to the rarity of this abnormality.
- Bone Marrow: 2 mL EDTA tube. Sodium heparin acceptable.
- Peripheral Blood: 5 mL EDTA tube. Sodium heparin acceptable.
Note: Test is RNA-based, NOT suitable for Freeze & Hold option.
Use cold pack for transport, making sure cold pack is not in direct contact with specimen. Ship same day as drawn whenever possible; specimens <7 days old preferred.