Genotyping of chimerical BCR-ABL1 RNA in chronic myeloid leukemia by integrated DNA chip

Feasibility of Qualitative Testing of BCR-ABL and JAK2 V617F in Suspected Myeloproliperative Neoplasm (MPN) Using RT-PCR Reversed Dot Blot Hybridization (RT-PCR RDB)

BACKGROUND

Defining the presence of BCR-ABL transcript in suspected myeloproliferative neoplasm is essential in establishing chronic myeloid leukemia. In the absence of BCR-ABL, the conventional diagnostic algorithm recommends JAK2 V617F mutation testing to support diagnosis of other MPN diseases such as polycythemia vera, essential thrombocythemia, and primary myelofibrosis. In certain cases of thrombocythemia, simultaneous upfront testing of both BCR-ABL and JAK2 may be desirable. We wanted to test the feasibility of multiplex detection of BCR-ABL transcript variants and JAK2 V617F mutation simultaneously using the reverse transcriptase polymerase chain reaction (RT-PCR)-based reverse dot-blot hybridization (RDB) method.

MATERIAL AND METHODS

Separate biotinylated RT-PCR primers were designed to amplify specific BCR-ABL transcripts and JAK2 V617F mutant alleles. Specific hybridization of RT-PCR products with arrays of membrane-bound probes followed by colorimetric development would allow simultaneous visualization of BCR-ABL and/or JAK2 mutant transcripts in a given specimen. To validate the RDB method, we used cDNA specimens previously referred to our laboratory for routine clinical testing of BCR-ABL and/or JAK2.

RESULTS

The limit of detection or analytical sensitivity of the RDB method using cDNA specimens was 0.5% and 6.25% in detecting BCR-ABL and JAK2 mutant transcripts, respectively. The diagnostic specificity and sensitivity to detect BCR-ABL and JAK2 were 100% and 92.3% (N = 38); and 100% and 100% (N = 27), respectively. RDB also detected BCR-ABL transcripts in 22% of JAK2 V617F mutation-positive samples (N = 14).

CONCLUSIONS

RT-PCR RDB is a promising qualitative multiplex method to detect BCR-ABL and JAK2 mutant transcripts simultaneously.