t(16;21)(q24;q22) in acute myeloid leukemia: case report and review of the literature.

摘要

Chromosome 21 and in particular band 21q22, the site of AML1 (RUNX1, CBFA2) gene, is among the most frequent targets of chromosomal translocations in leukemia observed in both de novo acute leukemia, therapy-related myelodysplastic syndromes (t-MDS), and acute myeloid leukemia (t-AML) . The 21q22 band has been involved in translocations with over 20 different partner chromosomal regions. The most frequent translocation is t(12;21)(p12;q22) seen in 25% of childhood acute lymphoblastic leukemia and t(8;21)(q22;q22) in 10% of AML mostly M2, leading to the fusion of the 5' region of the AML1 gene with the ETV6 (TEL) gene and with the RUNX1T1 (ETO, CBFA2T1) gene, respectively [2, 3]. Other rare translocations affecting 21q22 include t(1;21)(p36;q22), t(3;21)(q26;q22), t(16;21)(q24;q22), t(15; 21)(q21-22;q22), t(17;21)(q12;q22), and t(9;21)(p22;q22) . The t(16;21)(q24;q22) translocation has previously been reported in 16 cases with MDS/AML. Here, we present a new case of AML-M4 with t(16;21)(q24;q22) translocation as the sole clonal abnormality associated with AML1 gene rearrangement.