title: Loss of imprinting of long QT intronic transcript 1 in colorectal cancer.
abstract: Loss of imprinting (LOI) of the insulin-like growth factor 2 (IGF2) and H19 genes on human chromosome 11 has been found not only in childhood tumors but also in common adult cancers including colorectal cancer. Recently, a transcript called LIT1 (long QT intronic transcript 1) has been identified within the KvLQT1 locus on chromosome 11. LIT1 is expressed preferentially from the paternal allele and is transcribed in most human tissues. LOI of LIT1 was found in a considerable number of Beckwith-Wiedemann syndrome (BWS) patients, suggesting that it is associated with the etiology of BWS. Since LOI of IGF2 was observed in association with overexpression of IGF2 in colorectal cancer in our previous study, we examined the status of genomic imprinting of LIT1 and H19 in comparison with IGF2 in colorectal cancer. We examined 44 surgically dissected colorectal cancer tissues. Ten of them represented informative cases for LIT1. None of these patients exhibited loss of heterozygosity (LOH) of LIT1, and LOI of LIT1 was observed in 4 of the 10 (40%) informative patients, but not in non-cancerous tissues. Neither LOH nor LOI of H19 was observed. LOI of IGF2 was observed in 4 of 18 (22%) informative patients. These results suggest that LOI of LIT1 is frequently observed in colorectal cancer and may be a useful marker for diagnosis of colorectal cancer.
authors.affiliation: Second Department of Internal Medicine, School of Life Sciences, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Tanaka
authors.forename: G
authors.initials: G
authors.lastname: Shiota
authors.forename: M
authors.initials: M
authors.lastname: Meguro
authors.forename: K
authors.initials: K
authors.lastname: Mitsuya
authors.forename: M
authors.initials: M
authors.lastname: Oshimura
authors.forename: H
authors.initials: H
authors.lastname: Kawasaki
mesh_terms: D002880:Chromosomes, Human, Pair 11; D015179:Colorectal Neoplasms / Q000235:genetics*; D018392:Genomic Imprinting; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000235:genetics; D051656:KCNQ Potassium Channels; D051657:KCNQ1 Potassium Channel; D019656:Loss of Heterozygosity; D015221:Potassium Channels / Q000235:genetics*; D024642:Potassium Channels, Voltage-Gated; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated / Q000235:genetics
chemical_list: C094335:H19 long non-coding RNA; D051656:KCNQ Potassium Channels; D051657:KCNQ1 Potassium Channel; C496909:KCNQ1 protein, human; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D007335:Insulin-Like Growth Factor II