title: Microsatellite instability confounds engraftment analysis of hematopoietic stem-cell transplantation.
abstract: Polymorphic short tandem-repeat, or microsatellite, loci have been widely used to analyze chimerism status after allogeneic hematopoietic stem-cell transplantation. In molecular diagnostic laboratories, it is recommended to calculate mixed chimerism for at least 2 informative loci and to avoid microsatellite loci on chromosomes with copy number changes. In this report, we show that microsatellite instability observed in 2 patients with acute leukemia may confound chimerism analysis. Interpretation errors may occur even if 2 to 3 loci are analyzed because of length variation in multiple microsatellite loci. Although microsatellite loci with length variation should not be selected for chimerism analysis, the presence of microsatellite instability, like copy number alteration because of aberrant chromosomes, provides evidence of recurrent or residual cancer cells after hematopoietic stem-cell transplantation.
authors.affiliation: Departments of *Pathology ‡Oncology, Johns Hopkins University School of Medicine, Johns Hopkins Hospital, Baltimore, MD †Department of Medical Genetics and Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Li-Hui
authors.initials: LH
authors.lastname: Tseng
authors.forename: Jih-Luh
authors.initials: JL
authors.lastname: Tang
authors.forename: Lisa
authors.initials: L
authors.lastname: Haley
authors.forename: Katie
authors.initials: K
authors.lastname: Beierl
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Gocke
authors.forename: James R
authors.initials: JR
authors.lastname: Eshleman
authors.forename: Ming-Tseh
authors.initials: MT
authors.lastname: Lin
mesh_terms: D000208:Acute Disease; D064591:Allografts; D000818:Animals; D046528:Chimerism; D002877:Chromosomes, Human / Q000235:genetics* / Q000378:metabolism; D056426:Genetic Loci; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007938:Leukemia / Q000235:genetics* / Q000473:pathology / Q000628:therapy*; D053842:Microsatellite Instability; D018895:Microsatellite Repeats