dup(15)(q15q25) as a sole anomaly in a case of polycythemia vera: Trisomy 15 in hematological disorders revisited. A. Adeyinka, S. Wei, J. Sanchez. Dept Medical Genetics, Henry Ford Health System, Detroit, MI.
   Trisomy 15 as a sole clonal autosomal anomaly in hematological malignancies reportedly is uncommon. Nonetheless, trisomy 15 as a sole abnormality has been documented in a wide range of hematological disorders, especially myelodysplastic disorders. However, complicating an understanding of the possible role of this anomaly in tumorigenesis and/or tumor progression are its frequent association with loss of the Y chromosome in males, the fact that it is commonly seen in older patients and its presence in individuals without hematological malignancy. We report a cytogenetic and fluorescent in situ hybridization (FISH) analysis in a case of polycythemia vera with dup(15)(q15q25). G-banded metaphase cells obtained from short-term culture of a bone marrow sample from an 87-year-old female patient were 46,XX,dup(15)(q15q25)[5]/46,XX[15]. The dup(15q) was further delineated by FISH studies using whole chromosome 15 painting probe (WCP15), SNRPN, PML, and D15Z1 probes. FISH analysis confirmed duplication of 15 q-arm distal to SNRPN and encompassing the PML locus. Furthermore, we identified through a search of our database of cytogenetically characterized hematologic disorders, 22 cases with trisomy 15 as the sole autosomal anomaly. Including the case of dup(15q), all 23 samples with gain of 15q were from older patients, age range 65-92 years with a median age of 81 years, who were mostly males (70%). In nine (1 female and 8 males) (39%) of the 23 individuals, trisomy 15 was associated with loss of a sex chromosome. Among all 23 individuals, a wide range of hematological conditions was associated with trisomy 15/gain of 15q, including hematological malignancies and non-neoplastic marrow. Our data show that trisomy 15 is associated with hematological malignancies as well as non-neoplastic hematological conditions, making it a poor marker of malignancy. Nonetheless, our present finding of dup(15)(q15q25) as a sole abnormality in polycythemia vera and a previously published case of acute promyelocytic leukemia with dup(15)(q15q26) as a sole abnormality suggest that duplication of genes on 15q may be of pathogenic importance in some hematological malignancies.