[1472] Myelodysplastic Syndrome/Acute Myeloid Leukemia with t(3;21)(q26;q22) Are Commonly Therapy Related Diseases Associated with Poor Outcome

Shaoying Li, C Cameron Yin, L Jeffrey Medeiros, Gary Lu, Pei Lin. UT MD Anderson Cancer Center, Houston, TX

Background: The t(3;21)(q26;q22) with disruption of 3q26/EVI1 gene is a rare abnormality in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). The clinical pathologic features of MDS/AML with t(3;21) and their distinction from MDS/AML with inv(3)/t(3;3) are not well defined.
Design: We studied 17 MDS/AML cases associated with t(3;21)(q26;q22) and further compared them with 17 MDS/AML cases associated with inv(3)(q21q26.2)/t(3;3)(q21;q26.2), as these entities share 3q26 locus abnormalities.
Results: The study group included 9 men and 8 women, with median age of 62 years (range, 13-81). One case was de novo AML and 16 cases were therapy-related, including 12 t-MDS (blasts, <15%) and 4 t-AML (blasts, 33-50%). All cases showed multilineage dysplasia, but small hypolobated megakaryocytes, although common in cases of MDS/AML associated with inv(3)/t(3;3), were rare in cases with t(3;21) and no patient had thrombocytosis. Isolated t(3;21)(q26;q22) was identified in 5 cases (29%) while the other 12 cases had additional cytogenetic aberrations including -7/7q (9/17), -5/5q (1/17), and/or a complex karyotype (7/17). All patients died with 1-year and 2-year survival of 35% and 6%, respectively. There was no significant difference of the overall survival (OS) between patients with and without -7/7q or patients with and without a complex karyotype (p>0.05). Despite the similarities in age, gender, and concurrent cytogenetic abnormalities (-7/7q, -5/5q, or a complex karyotype), t(3;21) occurred almost exclusively in the therapy-related setting (16/17, 94%), compared with inv(3)/t(3;3) cases that occurred either de novo or after therapy (6/17, 35%) (p=0.001). The median OS was much shorter in MDS/AML with t(3;21) than that in MDS/AML with inv(3)/t(3;3) (4.7 months vs 14 months, p=0.03).
Conclusions: We conclude that though multilineage dysplasia and frequent association with -7 were overlapping features, the MDS/AML cases with t(3;21) was more often associated with therapy-related diseases and had a shorter survival than patients with inv(3)/t(3;3).
Category: Hematopathology

Monday, March 19, 2012 1:30 PM

Platform Session: Section C, Monday Afternoon


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