[Successful selection of chemotherapy based on cell surface antigens in a patient with mixed phenotype acute...

Area of Science:

• Hematology
• Oncology
• Clinical Pathology

Background:

• Mixed phenotype acute leukemia (MPAL) is a rare and challenging hematologic malignancy.
• Standard treatment protocols for MPAL are not well-established, necessitating individualized therapeutic strategies.

Observation:

• A 47-year-old male presented with fatigue and peripheral blast cells.
• Bone marrow examination revealed myeloperoxidase-positive, esterase-negative leukemic cells.
• Flow cytometry showed aberrant expression of lymphoid (CD2, cyCD3, CD5, TdT) and myeloid (CD13) markers.

Findings:

• Cytogenetic analysis revealed a karyotype with a t(1;11) translocation and trisomy 11.
• The patient was diagnosed with mixed phenotype acute leukemia, T/myeloid, NOS.
• Initial induction chemotherapy for acute lymphoblastic leukemia (ALL) failed to achieve complete remission (CR).
• Residual disease expressing CD13, CD33, and myeloperoxidase (MPO) was detected by flow cytometry.
• Subsequent re-induction chemotherapy for acute myeloid leukemia (AML) resulted in CR.

Implications:

• This case underscores the importance of precise immunophenotyping and cytogenetic analysis in diagnosing and classifying MPAL.
• Personalized chemotherapy selection, guided by flow cytometry, can be effective in achieving remission in refractory MPAL.
• Further research into optimal treatment strategies for MPAL is warranted to improve patient outcomes.