Reverse transcription followed by Quantitative Real-Time Polymerase Chain Reaction (PCR)
Greater than 95% of acute promyelocytic leukemia (APL) cases harbor a t(15;17) translocation. This rearrangement results in the fusion of the PML and retinoic acid receptor alpha (RARA) genes located on chromosomes 15 and 17 respectively. Three breakpoint regions within the PML gene can be involved, resulting in three possible PML/RARA fusion types: bcr1 (long), bcr2 (variable), and bcr3 (short). This test quantitatively detects all three PML/RARA transcript variants in peripheral blood and bone marrow. Testing for PML/RARA can assist in the diagnosis, clinical management, and monitoring of APL.
Interpretive report provided
The limit of detection of this assay is 1/5,000 to 1/10,000 cells carrying the PML/RARA fusion. Mutations may not be detected in samples with a neoplastic burden below this level. This assay will not detect atypical rearrangements outside of the tested breakpoint regions or rearrangements involving uncommon RARA fusion partners such as NPM1, STAT5B, NUMA, PLZF. Specimens older than 48-72 hours may result in failed testing due to RNA degradation.
2 - 7 days
Collect blood or bone marrow in a lavender top tube. Refrigerate and send intact blood or bone marrow specimen within 48 hours of collection. Fresh tissue (preferably 0.5cm3, sent in RPMI) and fresh aspirates or body fluids are acceptable. Refrigerate and send, preferably within 24 hours. Frozen tissue specimens – preferably frozen with 1 hour of collection – may also be sent frozen on dry ice. Fresh cell suspensions in RPMI should be refrigerated and sent, preferably within 48 hours. Frozen cell suspensions – preferably frozen with 1 hour of collection – may also be sent frozen on dry ice.