title: Trisomy 15 is frequently observed as a minor clone in patients with Anemia/MDS/NHL and as a major clone in patients with AML.
abstract: Trisomy 15 as the sole karyotypic aberration is an uncommon clonal cytogenetic aberration in hematological malignancies, making its significance unclear. Previous studies have reported relations of trisomy 15 with low-grade myelodysplasia or a benign age-related phenomenon associated with loss of the Y chromosome. To define the significance of trisomy 15, we conducted a retrospective study of all examples of trisomy 15 accessed in our laboratories. Trisomy 15 was observed as a clonal abnormality (> or =2 cells) in 17 cases and nonclonal (single cell) in 9 cases. The majority of cases (14/17 clonal cases) had a minor clone (5-35% of metaphase cells) of trisomy 15. The minority of cases (3/17) had a major clone (80-95% of metaphase cells) of trisomy 15. Two of these 3 cases were diagnosed as having acute myelocytic leukemia. Fluorescence in-situ hybridization (FISH) with the use of a chromosome 15-specific alpha-satellite probe was performed on 3 of 17 clonal cases and on 3 of 9 nonclonal cases. FISH results revealed the presence of a minor clone (from 3 to 5 of 700 interphase cells) in 5 of them, 2 of which had trisomy 15 in 20% of metaphase cells. These results may indicate that the 20% of trisomy 15 are very likely an overrepresentation of a very minor clone that could be transitory. In summary, the analysis of our cytogenetic and FISH results revealed the presence of two types of trisomy 15 clones: a minor clone that could be transitory or indolent and a major clone that could be of a neoplastic nature.
authors.affiliation: Department of Pediatrics, Health Science Center, Saint Louis University and Pediatrics Research Institute, St. Louis, MO, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Batanian
authors.forename: M L
authors.initials: ML
authors.lastname: Slovak
authors.forename: A
authors.initials: A
authors.lastname: Mohamed
authors.forename: S
authors.initials: S
authors.lastname: Dobin
authors.forename: F W
authors.initials: FW
authors.lastname: Luthardt
authors.forename: E A
authors.initials: EA
authors.lastname: Keitges
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000235:genetics*; D002884:Chromosomes, Human, Pair 15; D015331:Cohort Studies; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D015470:Leukemia, Myeloid, Acute / Q000235:genetics*; D008228:Lymphoma, Non-Hodgkin / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014314:Trisomy