Analysis of Acute Myeloid Leukemia in Korean Patients with Sole Trisomy 6

Autosomal trisomy as a sole cytogenetic change has been described in several hematologic malignancy cases, but the number of reports on the association between specific morphologies and individual structural cytogenetic abnormalities are few [1]. Trisomy 8 is the most common abnormality in myeloproliferative neoplasms (MPN), MDS, MDS/MPN and AML, and trisomy 4, 9, 11, 13, and 21 have been reported to be associated with myeloid disorders [1, 2]. Here, we describe three patients with AML and show that trisomy 6 is the sole clonal cytogenetic bone marrow abnormality. The patients were adults without previous hematologic disorders, and were initially diagnosed with AML M1, M2, and M4, according to the French-American-British (FAB) classification. These patients received chemotherapy with or without allogenic peripheral blood stem cell transplantation (PBSCT), and showed variable clinical outcomes. The first case of sole trisomy 6 abnormality was reported in a patient with aplastic anemia (AA) [2]. The other reports showed that trisomy 6 was associated with hypoplastic bone marrow, dyserythropoiesis and AML prior to hypocellular marrow with MDS [3-5]. To establish a relationship between the clonality of AML and a single trisomy 6 abnormality, we searched PubMed (http://www.ncbi.nlm.nih.gov/pubmed) with combinations of the search terms “AML” and “trisomy 6”. Subsequently, we identified ten reports describing 18 cases of AML presenting with trisomy 6 as the sole karyotypic abnormality. The laboratory findings and clinical features, including those of the three cases reported here, and those of previously reported cases are summarized in Table 1. Including our three cases, there were 10 female and 11 male patients, including 3 children and 1 infant. The mean age was 41.4 yr, with a range of 22 months to 82 yr. Their bone marrow (BM) cellularity was variable, but it showed a hypoto normocellular tendency. Although some cases were reported without the results of a complete blood count (CBC), we found six cases of cytopenia in a single cell line (five cases of thrombocytopenia and one case of anemia), three cases of cytopenia in two cell lines (both anemia and thrombocytopenia), and one case of pancytopenia. Leukocytosis was found in six of the 11 cases with CBC results. There were four cases each of M1 and M2, three cases of M4, two cases of M5, and one case of M7 diagnosed according to FAB criteria; four cases of the 21 were diagnosed as having AML without additional categorization. Case number (No.) 10 was suspicious for AML-M3, but no rearrangement of t(15;17)(q22;q12) was identified, so it was not presumed to be AML-M3. Case No.14 was reported as relapsed