Transient trisomy 8 abnormality in Philadelphia-negative cells during imatinib mesylate treatment of chronic myelogenous leukemia.

We investigated chronic myelogenous leukemia (CML) patients who developed trisomy 8 abnormalities in Philadelphia-negative (Ph-) cells during imatinib mesylate treatment to evaluate the clinical outcome and laboratory features. Of the 470 CML patients, 1.5% (n = 7) developed trisomy 8 chromosomal abnormalities in Ph- cells. The median interval of the first trisomy 8 observation was 12 months. Our follow-up cytogenetic evaluations revealed that six of the patients demonstrated a complete or partial cytogenetic response and that all of the six patients revealed no dysplastic changes following a bone marrow examination. Moreover, the percentage of trisomy 8 in metaphase karyotyping has decreased in five of the seven subjects. In conclusion, these results suggest that the emergence of trisomy 8 in Ph- cells is transient and not related to therapy-related myelodysplasia or acute leukemia.