Coexistence of P190 and P210 BCR/ABL transcripts in chronic myeloid leukemia blast crisis resistant to imatinib.

Introduction: Philadelphia chromosome (Ph) is a hallmark of chronic myeloid leukemia (CML), which exists in more than 90% CML and in 3% to 40% acute lymphoblastic leukemia (ALL).

Case Description: A 25-year-old man was diagnosed with CML in chronic phase. He first received treatment with hydroxyurea, achieving hematological remission and following imatinib mesylate for main treatment. A year later, he began to appear unexplained high fever with ineffective antibiotic treatment and bone morrow and blood tests indicated blast crisis. Both BCR/ABL 210 and BCR/ABL 190 fusion transcript were positive. Imatinib resistance was confirmed by a screening for ABL kinase domain E255K mutations, and dasatinib was administered. After two months, the patient went on to hematological remission.

Discussion And Evaluation: During medical treatment for CML, we experienced a relatively rare case with co-expression of the p210 and p190 encoding BCR-ABL transcripts in blastic phase. Imatinib resistance was confirmed and remission wasn't easily obtained, yet dasatinib was helpful. When resistance emerges, the treatment options include increasing the daily dose of imatinib, or combining imatinib with other agents. Of course, dasatinib, nilotinib and bone marrow transplantation are good choice as well.

Conclusions: The presence of p-190 transcript in CML may be related to progression of the disease. Thus monitoring the resistance of imatinib in CML patients, especially for advanced phase CML and BCR-ABL ALL, may be meaningful to guide clinical treatment and predict the prognosis.