Constitutional pericentric inversion 9 in Korean patients with chronic myelogenous leukemia

Although the pericentric inversion of chromosome 9, inv(9)(p11q13), is generally considered a normal variation, it is also associated with solid tumors and several hematologic malignancies such as biphenotypic acute leukemia, ALL, AML, and myeloproliferative neoplasms. However, to the best of our knowledge, there have been no reports that suggest an association between CML and constitutional pericentric inversion of chromosome 9. The purpose of this retrospective study was to investigate the frequency and clinical features of CML patients with concomitant inv(9) and t(9;22)(q34;q11.2) variation at our institution.

We reviewed the bone marrow chromosome database entries between October 2006 and December 2008 to identify patients with concomitant inv(9) and t(9;22) variations. Laboratory and clinical data of the patients were obtained from the electronic medical record system.

Among the 51 CML patients, 4 (7.8%) had concomitant inv(9) and t(9;22) variations.

Although the association between inv(9) variation and CML is still controversial, we believe that hematologists should consider the role of constitutional inv(9) variation in CML patients to avoid overlooking the impaired engraftment potential of hematopoietic stem cells harboring inv(9). Therefore, we suggest that more effort should be invested to develop cytogenetic tests for detecting constitutional inv(9) variation in CML patients.