Background: Heterogeneous response to tyrosine kinase inhibitors (TKIs) and progress to advance phases, still is a significant clinical problem. These are attributed to additional mutations in mutated non-ABL1 genes. we aimed to determine prognostic effects of ASXL1 mutations as a biomarker for diverse treatment response and disease progression to aid clinical management.

Methods: We performed ASXL1 gene mutational screening in 80 Ph⁺CML patients at different phases and 10 healthy control by direct sequencing method. Multiplex and qRT-PCR, standard chromosome banding analysis were used to determine BCR-ABL1 transcript type, molecular and cytogenetic responses respectively.

Results: overall, four type mutations were identified in 11.25% of the patients. There was significant difference regarding mutation frequency between chronic and advance phases (P = 0.0002), sokal risk score (P = 0.0001), smoking (P = 0.02) and mean of during time of imatinib treatment (P = 0.009) between patients with and without ASXL1 mutations. ASXL1 mutations frequency had a bias toward younger than older and women than men, but no significant (P > 0.05). ASXL1 mutations were found more recurrently in patients carrying ABL1 KD mutations (P = 0.003). The risk of increasing resistance and disease progression in patients with ASXL1 mutations was 32 and 63 fold higher than those without mutations respectively (P = 0.01; P = 0.0002). The risk of ASXL1 mutations presence in patients with b2a2 transcript type was much higher than b3a2 type (P = 0.02, OR = 10).

Conclusion: Our findings suggest that ASXL1 mutations may be favorable predictive biomarkers to determine the best TKI for each patient, and to prevent CML progression.