Identification of a cryptic submicroscopic deletion using a combination of fluorescence in situ hybridization and array comparative genomic hybridization in a t(3;5)(q25;q35)-positive acute myeloid leukemia patient: A case report and review of the literature

RATIONALE: The advent of high-resolution genome arrays including array comparative genomic hybridization (aCGH) has enabled the detection of cryptic submicroscopic deletions flanking translocation breakpoints in up to 20% of the apparently “balanced” structural chromosomal rearrangements in hematological disorders. However, reports of submicroscopic deletions flanking the breakpoints of t(3;5)(q25;q35) are rare and the clinical significance of submicroscopic deletions in t(3;5) has not been explicitly identified. PATIENT CONCERNS: We present a 47-year-old man with acute myeloid leukemia. G-banding analysis identified t(3;5)(q25;q35). DIAGNOSIS: Array CGH-based detection initially confirmed only the deletion of chromosome 3. Further characterization using fluorescence in situ hybridization identified a cryptic submicroscopic deletion including 5′ MLF1-3′ NPM1 flanking the breakpoint on the derivative chromosome 3. INTERVENTIONS: The patient started “7+3” induction chemotherapy with cytosine arabinoside and daunorubicin, and subsequently received 2 cycles of high-dose intermittent acronym of cytosine arabinoside or cytarabine. OUTCOMES: The patient did not undergo complete remission and died from an infection due to neutropenia. LESSONS: Haploinsufficiency of NPM1 or other deleted genes, including SSR3, may be responsible for the phenotype of t(3;5)(q25;q35)-positive myeloid neoplasms with submicroscopic deletions.