Short communication Deletion of chromosome arm 15q in a case of minimally differentiated hypoplastic AML-M0

Abstract Deletion of the long arm of chromosome 15 is known as a rare but recurrent chromosomal abnor-mality in myeloid malignancies. We report a novel case of minimally differentiated hypoplasticacute myeloid leukemia (AML M0) in a patient who initially had a normal karyotype, but clonalinterstitial deletion of chromosome 15, del(15)(q11.2q22), coincided with increment of leukemiccells a year later. We also summarize 18 published cases with myeloid malignancies and this chro-mosomal abnormality. 2008 Elsevier Inc. All rights reserved. 1. IntroductionMinimally differentiated acute myeloid leukemia (AML-M0) is a subtype of AML characterized by a negative cyto-chemical myeloperoxidase reaction at light microscopiclevel, expression of CD13 or CD33 (or both), and absenceof lymphoid markers [1e5]. Several reports have describedthecytogeneticfeaturesofAML-M0[6e10].Mostoftheab-normalities were unbalanced, and chromosomes 5, 7, 8, 11,and 13 were frequently affected. In these abnormalities, 5/5q , 7/7q , and trisomy 13 were highly associatedwithAMLM0 [7,9,10].Furthermore,AML M0 was charac-terized by a high incidence of complex aberrant karyotype.To our knowledge, however, a clonal interstitial deletion ofthe long arm of chromosome 15, del(15)(q11.2q22) has notpreviously been reported in AML-M0.Abnormalities of chromosome 15 are commonly ob-served in AML. The most frequent aberration ist(15;17)(q22;q21), which is specific for acute promyelo-cytic leukemia (APL) and is associated with a favorableprognosis. The retinoic acid receptor alpha gene (RARA)on chromosome 17q21.1 is fused to the promyelocyticleukemia gene (PML) on chromosome 15q22 in almostall APL cases [11e15]. Other translocations involving15q11~q13 and 15q13~q15 also have been noted in diffuselarge cell lymphomas and childhood acute lymphoblasticleukemia, respectively [16,17]. On the other hand, a dele-tion of the long arm of chromosome 15 (deletion 15q) oc-curs infrequently in hematological malignancies. To date,only 18 patients with myeloid malignancies and deletion15q have been reported [18e27]. However, the exact bio-logical significance of this chromosomal abnormality re-mains obscure, with limited information in the literature.Accumulation of data on deletion 15q might therefore ben-efit the search for unknown genes involved in the pathogen-esis of this type of myeloid malignancies.2. Case reportA 70-year-old woman with a history of tuberculouslymphadenitis during childhood was referred to the Hema-tology and Oncology service at Mie University Hospital forevaluation of leukocytopenia and anemia in July 2004. Thehematological parameters were as follows: hemoglobin(Hb) 9.8 g/dL, platelet count 313 10