CO-OCCURRENCE OF BCR-ABL1/JAK2V617F DOUBLE POSITIVE IN TUNISIAN
POSTER 33
RESISTANT CHRONIC MYELOID LEUKEMIA PATIENTS
Rim Frikha1, Fatma Turki1, Moez Elloumi2 and Hassen Kamoun1
(1)Medical Genetic department, Sfax, Tunisia
(2)Department of Hematology, Sfax, Tunisia
Objective: Diagnoses of myeloproliferative disorder (MPD) is based on molecular marker.
Chronic Myeloid Leukemia (CML) and Myeloproliferative neoplasms were considered
mutually exclusive and co-existence of BCR/ABL1 and JAK2 mutation is a rare phenomenon.
Here, we present two cases of co-existence of BCR-ABL and JAK2V617F positivity. We
characterize the course of the disease, mainly the minimal residual disease (MRD).
Methods: Quantitative assessment of the BCR-ABL transcript was performed using the
Cepheid Xpert BCR-ABL ultra assay. Genotyping of JAK2 mutation was achieved by ASO-PCR.
Results: The two cases was initially managed as CML and treated by TKI inhibitors. The first
one was diagnosed in 2010. He started the first line of TKI, and then switched to second line
without obtaining a major molecular response. JAK2V617F positivity was diagnosed. The
second patient showed CML phenotype with coexistence of BCR/ABL1 and JAK2 mutation at
diagnosis. Molecular monitoring reveals a high BCR-ABL1 transcript level (20%) at the last
follow-up (12 months)
Conclusion: Emphasis should be placed on the detection of JAK2 mutation in CML resistant
patients to the TKI inhibitors. Our finding suggests that JAK2V617F/BCR-ABL double positivity
may be a potential marker of resistance in CML. Moreover, the combination of JAK and TKI
inhibitors might be effective and potentially be guided by molecular monitoring of minimal
residual disease (MRD).