Short communication Two childhood cases of acute leukemia with t(16;21)(p11.2;q22): second case report of infantile acute lymphoblastic leukemia with unusual type of FUS-ERG chimeric transcript Seung Hwan Oh a,1 , Tae Sung Park b,1 , Jong Rak Choi c , Sanggyu Lee d , Sun Young Cho b , So Young Kim b , Juwon Kim c , Ji Kyoung Park e , Sae Am Song a , Ja Young Lee a , Jeong Hwan Shin a , Hye Ran Kim a , Jeong Nyeo Lee a, * a Department of Laboratory Medicine, Inje University College of Medicine, Gaegeum-dong, Busanjin-gu, Busan 614-735, Korea b Department of Laboratory Medicine, School of Medicine, Kyung Hee University, 1 Hoegi-dong, Dongdaemun-gu, Seoul 130-702, Korea c Department of Laboratory Medicine, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752, Korea d School of Life Science and Biotechnology, Kyungpook National University, 1370 Sankyuk-dong, Buk-gu, Daegu 702-701, Korea e Department of Pediatrics, Inje University College of Medicine, Gaegeum-dong, Busanjin-gu, Busan 614-735, Korea Received 8 February 2010; received in revised form 30 March 2010; accepted 7 April 2010 Abstract We report two childhood cases of acute leukemia with t(16;21)(p11.2;q22) and FUS-ERG rear- rangements. Patient 1 (14 years old) was initially diagnosed with acute myeloid leukemia. Chromo- some study showed a t(16;21)(p11.2;q22) clone in more than one third of the cells analyzed, and further investigation with reverse-transcriptase polymerase chain reaction, cloning, and sequencing confirmed FUS-ERG rearrangement (type B). Patient 2 (8 months old) was diagnosed with acute lymphoblastic leukemia (ALL) on the basis of bone marrow morphology and immunophenotyping. Chromosome study revealed a 45,XY,-16,der(21)t(16;21)(p11.2;q22) in 50% of the cells analyzed. Further studies for the detection of a FUS-ERG chimeric transcript were conducted, and an unusual type of FUS-ERG rearrangement was discovered, which has been reported in only three patients including a 1-year-old infant with ALL. Although more clinical studies are necessary, we believe that a possible association between ALL and a specific type of FUS-ERG fusion transcript might be considered, especially in childhood cases with t(16;21). Ó 2010 Elsevier Inc. All rights reserved. 1. Introduction As the 2008 World Health Organization classification has made the diagnosis of acute myeloid leukemia (AML) possible by the concurrent detection of genetic rearrange- ments RUNX1/RUNX1T1, PML/RARA, and CBFB/MYH11, even without a blast count of more than 20% in the marrow and peripheral blood, molecular genetic markers including recurrent cytogenetic abnormalities have become more important [1]. Although t(16;21)(p11.2;q22) or FUS-ERG rearrangement is relatively rare in hematologic malignan- cies, it is now considered as a nonrandom genetic aberration in myeloid neoplasms such as de novo AML, myelodysplas- tic syndrome (MDS) evolved to AML, and even blast crisis of chronic myelocytic leukemia (CML), as well as Ewing’s tumors [2,3]. For this reason, t(16;21) might be regarded clin- ically as a myeloid-specific leukemia marker in hematologic malignancies. However, t(16;21) or FUS-ERG rearrange- ment has been reported very rarely in acute lymphoblastic leukemia (ALL) [4,5]. In this study, we present childhood cases of AML and ALL with t(16;21) and different-sized FUS-ERG fusion transcripts. We also suggest a possible association between infantile ALL and a specific type of FUS-ERG rearrangement. 2. Materials and methods 2.1. Clinical presentation Patient 1 A 14-year-old boy who had intermittent abdominal pain for 4 weeks was admitted to the Inje University Hospital in February 2008. His initial complete blood count (CBC) * Corresponding author. Tel.: þ82-51-890-6862; fax: þ82-51-893- 1562. E-mail address: jeong418@medimail.co.kr (J.N. Lee). 1 Both authors contributed equally to this work and each is considered first author. 0165-4608/$ e see front matter Ó 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.cancergencyto.2010.04.009 Cancer Genetics and Cytogenetics 200 (2010) 180e183