Abstract
Myeloid sarcoma (MS) is a tumor mass of myeloblasts or immature myeloid cells occurring in an extramedullary site. In this study, seven cases of MS [stomach (1), testis (1), skin (2), and lymph node (3)] and 3 synchronous and 1 followโup bone marrow (BM) samples were studied for genomic abnormalities using array comparative genomic hybridization (arrayโCGH). ArrayโCGH construction used โผ5,400 bacterial artificial chromosome clones from the RPCIโ11 library, spanning the human genome. Data were analyzed using the DNAcopy software and custom heuristics. All MS cases had genomic abnormalities detected by arrayโCGH. Unbalanced genomic abnormalities in five MS cases were confirmed by conventional cytogenetics (CC) and/or fluorescence in situ hybridization (FISH); these abnormalities included loss of 4q32.1โq35.2, 6q16.1โq21, and 12p12.2โp13.2 and gain of 8q21.2โq24.3, 8, 11q21โq25, 13q21.32โq34, 19, and 21. ArrayโCGH was also invaluable in identifying possible deletions, partner translocations, and breakpoints that were questionable by CC. The remaining two MS cases had genomic aberrations detected by arrayโCGH, but were not studied further by CC/FISH. Chromosome 8 was most commonly abnormal (3/7 cases). Identical genomic abnormalities were demonstrated in MS and in synchronous BM in two cases. These results demonstrate that arrayโCGH is a powerful tool to screen MS tissue for unbalanced genomic abnormalities, allowing identification of chromosome abnormalities when concurrent BM is nonanalyzable or nonleukemic. ยฉ 2005 WileyโLiss, Inc.