title: Deletion(20q) as the sole abnormality in plasma cell myeloma is not associated with plasma cells as identified by cIg FISH.
abstract: Deletion of 20q is a common finding in myeloid disorders but it is also observed in plasma cell myeloma (PCM). As a del(20q) in a patient receiving treatment for myeloma may indicate therapy-related myelodysplastic syndrome (t-MDS), it is important to differentiate chromosome abnormalities associated with myeloma from those reflecting t-MDS. We performed fluorescence in situ hybridization (FISH) using a 20q12 probe (D20S108) in conjunction with cytoplasmic immunoglobulin (cIg) staining in 20 PCM cases with a del(20q) in order to confirm the cell type involved. Of the nine cases studied with a clone showing a del(20q) as the sole abnormality, 8 of 9 demonstrated loss of the D20S108 signals in non-plasma cells only and 5 of 9 had either a confirmed myeloid malignancy in addition to PCM or showed evidence of dysplastic changes in the marrow; however, of the 11 patients with a del(20q) within a complex PCM karyotype, 4 of 11 showed loss of the D20S108 signals in plasma cells only and 7 of 11 showed no significant loss in either plasma cells or non-plasma cells. Therefore, our results indicate that a del(20q) as the sole abnormality in PCM is present in non-plasma cells and, therefore, suggests the presence of an associated myeloid malignancy.
authors.affiliation: Victorian Cancer Cytogenetics Service, St. Vincent's Hospital Melbourne, Fitzroy, Australia. jo.white@svhm.org.au
authors.forename: Joanne S
authors.initials: JS
authors.lastname: White
authors.forename: Adrian
authors.initials: A
authors.lastname: Zordan
authors.forename: Crisoula
authors.initials: C
authors.lastname: Batzios
authors.forename: Lynda J
authors.initials: LJ
authors.lastname: Campbell
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002467:Cell Nucleus / Q000378:metabolism; D002872:Chromosome Deletion; D002890:Chromosomes, Human, Pair 20 / Q000235:genetics*; D003593:Cytoplasm / Q000378:metabolism; D015342:DNA Probes / Q000378:metabolism; D005260:Female; D006801:Humans; D007136:Immunoglobulins / Q000378:metabolism*; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000235:genetics* / Q000473:pathology*; D010950:Plasma Cells / Q000473:pathology*
chemical_list: D015342:DNA Probes; D007136:Immunoglobulins