Detection of the JAK2^V617F mutation in myeloproliferative disorders by melting curve analysis using the lightcycler system

Context.-A specific mutation, JAK2^V617F, was recently recognized as having diagnostic value for myeloproliferative disorders. No practical assay is currently available for routine use in a clinical laboratory. Objective.-We report the development of a real-time polymerase chain reaction melting curve analysis assay that is appropriate for molecular diagnostics testing. Design.-Specific primers and fluorescence resonance energy transfer probes were designed, and patients with a previously diagnosed myeloproliferative disorder, de novo acute myeloid leukemia, or reactive condition were selected. The DNA was extracted from fresh and archived peripheral blood and bone marrow specimens, and realtime polymerase chain reaction melting curve analysis was performed on the LightCycler platform (Roche Applied Science, Indianapolis, Ind). Results.-The JAK2 region was successfully amplified, and wild-type amplicons were reproducibly discriminated from JAK2^V617F amplicons. Titration studies using homozygous wild-type and mutant cell lines showed the relative areas under a melting curve were proportional to allele proportion, and the assay reliably detected one mutant in 20 total cells. JAK^V617F was identified in patients previously diagnosed with a myeloproliferative disorder or acute myeloid leukemia transformed from myeloproliferative disorder, whereas a wild-type genotype was identified in patients with reactive conditions or de novo acute myeloid leukemia. Conclusions.-These findings demonstrate the suitability of this assay for identifying JAK2^V617F in a clinical laboratory setting. Furthermore, the semiquantitative detection of JAK2 ^V617F in archived specimens provides a new tool for studying the prognostic significance of this mutation.