title: Loss of imprinting in normal tissue of colorectal cancer patients with microsatellite instability.
abstract: Loss of imprinting (LOI) is an epigenetic alteration of some cancers involving loss of parental origin-specific expression of imprinted genes. We observed LOI of the insulin-like growth factor-II gene in twelve of twenty-seven informative colorectal cancer patients (44%), as well as in the matched normal colonic mucosa of the patients with LOI in their cancers, and in peripheral blood samples of four patients. Ten of eleven cancers (91%) with microsatellite instability showed LOI, compared with only two of sixteen tumors (12%) without microsatellite instability (P < 0.001). Control patients without cancer showed LOI in colonic mucosa of only two of sixteen cases (12%, P < 0.001) and two of fifteen blood samples (13%, P < 0.001). These data suggest that LOI in tumor and normal tissue identifies most colorectal cancer patients with microsatellite instability in their tumors, and that LO! may identify an important subset of the population with cancer or at risk of developing cancer.
authors.affiliation: Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
authors.forename: H
authors.initials: H
authors.lastname: Cui
authors.forename: I L
authors.initials: IL
authors.lastname: Horon
authors.forename: R
authors.initials: R
authors.lastname: Ohlsson
authors.forename: S R
authors.initials: SR
authors.lastname: Hamilton
authors.forename: A P
authors.initials: AP
authors.lastname: Feinberg
mesh_terms: D003106:Colon / Q000473:pathology; D003110:Colonic Neoplasms / Q000235:genetics / Q000473:pathology; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D005819:Genetic Markers; D018392:Genomic Imprinting; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000235:genetics*; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D018895:Microsatellite Repeats; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D012016:Reference Values
chemical_list: D005819:Genetic Markers; D007335:Insulin-Like Growth Factor II