Array-Based Comparative Genomic Hybridization Characterizes a Deletion Associated With a t(15;17) in Acute Promyelocytic Leukemia

The majority of de novo leukemias are characterized by well-known recurring translocations or inversions. In approximately 2% to 20% of these cases, deletions accompany these rearrangements. Because such deletions are undetectable by G-banding, aberrant fluorescence in situ hybridization (FISH) signal patterns are often the only indication of their presence. Array-based comparative genomic hybridization (a-CGH) permits examination of the entire genome at a resolution unattainable by G-banding or FISH. We present a case of a deletion of the derivative chromosome 17 of a t(15;17) in acute promyelocytic leukemia, the size and gene content Of which were characterized by a-CGH. We hypothesize that this patient's more aggressive disease course is due to loss of one or more of these genes. Such submicroscopic deletions involving the t(15;17) have only rarely been reported, and, to our knowledge, this is the first case in which a-CGH has been applied to its characterization.