Concomitant L248V with E225V mutation in BCR-ABL gene associated with rapid CML lymphoid blast crisis

Background Chronic Myeloid Leukemia (CML) is a myeloproliferative neoplasm characterized by the presence of the Philadelphia chromosome (Ph), resulting from the t(9;22)(q34;q11.2) translocation. Imatinib, a tyrosine kinase inhibitor, has revolutionized the treatment of CML. However, despite the initial response, some patients may progress to an advanced stage, such as a blast crisis. Case Presentation: We report a 40-year-old female who presented with CML chronic phase taking imatinib 400 mg/day and achieved a complete hematological response (CHR) after one month of treatment. She achieved suboptimal response in the third month (BCR-ABL positive 10.29% IS). However, five months into therapy, she developed a sudden lymphoid blast crisis with chromosomal aberrations involving chromosome 10 and 12. Molecular analysis detected concomitant L248V with partial exon 4 deletion and E225V mutations within the BCR-ABL1 fusion gene. The patient received intensive chemotherapy and dasatinib. Conclusion We report the first case of concomitant mutation of L248V with partial exon 4 deletion and E255V on BCR-ABL1 gene mutation which contributes to a sudden precursor B-cell lymphoid blast crisis.