What is BCR-ABL1?

BCR-ABL1 is a fusion gene created by a translocation between chromosome 9 (ABL1 gene) and chromosome 22 (BCR gene), known as t(9;22)(q34;q11), which produces the Philadelphia chromosome. This abnormality results in a constitutively active tyrosine kinase that drives unregulated cell proliferation—an essential hallmark in chronic myeloid leukemia (CML) and other leukemias. The fusion leads to the formation of different transcripts, namely e13a2, e14a2, e1a2, and e19a2, corresponding to p210, p190, and p230 proteins, which vary by disease type and severity.

Role of BCR-ABL1 in Leukemia

The BCR-ABL1 gene is the defining molecular marker in nearly 95% of CML patients and is also present in Ph-positive acute lymphoblastic leukemia (ALL) and rare cases of AML.

• p210 (e13a2/e14a2): Found in most CML patients

• p190 (e1a2): Common in Ph+ ALL, rare in CML

• p230 (e19a2): Rare variant seen in atypical CML or AML

These fusion proteins result in uncontrolled tyrosine kinase activity, contributing to the proliferation of abnormal white blood cells and suppression of normal hematopoiesis. Early detection and differentiation of these transcript types are critical for diagnosis, therapy selection, and monitoring.

About the TRUPCR® BCR-ABL1 Qualitative Detection Kit

The TRUPCR® BCR-ABL1 Qualitative qPCR Testing Kit is a real-time RT-qPCR assay designed for the qualitative detection of BCR-ABL1 fusion gene transcripts (e13a2, e14a2, e1a2, e19a2) in total RNA extracted from bone marrow or peripheral blood samples. It also includes a primer-probe set for ABL1 to assess RNA integrity and sample quality.

This ready-to-use kit eliminates the need for additional reagents or in-house optimization, helping standardize BCR-ABL1 detection across laboratories. It supports sensitive detection down to a single copy, ensuring even low-level disease presence can be confidently identified.

Principle and Workflow

The test workflow follows a robust two-step RT-qPCR protocol:

1. Reverse Transcription of total RNA into complementary DNA (cDNA)

2. Real-time PCR Amplification using transcript-specific primers for BCR-ABL1 fusion transcripts and ABL1 as internal control

Each fusion type is detected in dedicated wells, and fluorescence is measured in the FAM channel. The inclusion of cDNA synthesis reagents within the kit ensures streamlined processing and reduces inter-sample variability.

Clinical Application

This assay is suited for the initial diagnosis of CML and Ph+ ALL, as well as for baseline characterization before initiating tyrosine kinase inhibitor (TKI) therapy. Although qualitative, it forms a critical first step in molecular leukemia profiling by identifying which BCR-ABL1 transcript is present. The detection of rare variants like p230 adds value in less common clinical scenarios.
By incorporating ABL1 RNA control, the assay also safeguards against false negatives due to poor RNA integrity or failed reverse transcription, enhancing result reliability.