title: Detection of circulating prostate tumor cells: alternative spliced variant of PSM induced false-positive result.
abstract: RT-nested PCR has been introduced as a highly specific and sensitive assay method to detect the prostate-specific membrane antigen (PSM) mRNA in peripheral blood. However, appreciable percentages of false-positive cases have been reported. Additionally, primer sets reported previously could not discriminate between PSM and PSM', an alternatively spliced variant, mRNA. These isoforms can be produced from a single gene. Switches in alternative splicing patterns are often controlled with strict cell-type or developmental-stage specificity. Therefore, it is most important to discriminate between PSM mRNA and PSM' mRNA. Using our highly specific primer sets, PSM mRNA was detected in 3 of 24 peripheral blood samples of normal male volunteers (12.5%) and was not detected in peripheral blood of 11 normal female volunteers. PSM' mRNA was detected in 5 of 24 peripheral blood samples of normal male volunteers (20.8%) and in 4 of 11 of normal female volunteers (36.4%). PSM' mRNA induced false-positive results, it is important for genetic diagnosis of prostate cancer to discriminate between PSM and PSM' using our primer sets with high specificity. The advances in the uniquely designed primer sets may allow researchers to detect a real PSM mRNA without PSM' mRNA.
authors.affiliation: Center for Molecular Biology and Cytogenetics, SRL, Inc, Hino, Tokyo, Japan. hisatomi@srl.srl-inc.co.jp
authors.forename: Hisashi
authors.initials: H
authors.lastname: Hisatomi
authors.forename: Kumi
authors.initials: K
authors.lastname: Nagao
authors.forename: Mutsuji
authors.initials: M
authors.lastname: Kawakita
authors.forename: Tadashi
authors.initials: T
authors.lastname: Matsuda
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hirata
authors.forename: Shigeki
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Takaaki
authors.initials: T
authors.lastname: Nakamoto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Harasawa
authors.forename: Noboru
authors.initials: N
authors.lastname: Kaneko
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Hikiji
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Tsukada
mesh_terms: D000328:Adult; D000368:Aged; D017398:Alternative Splicing; D000951:Antigens, Neoplasm / Q000032:analysis / Q000097:blood* / Q000235:genetics*; D000954:Antigens, Surface; D001483:Base Sequence; D002268:Carboxypeptidases / Q000032:analysis / Q000097:blood / Q000235:genetics*; D016022:Case-Control Studies; D005189:False Positive Reactions; D005260:Female; D043425:Glutamate Carboxypeptidase II; D006801:Humans; D008297:Male; D008875:Middle Aged; D009360:Neoplastic Cells, Circulating / Q000276:immunology*; D016133:Polymerase Chain Reaction; D011471:Prostatic Neoplasms / Q000097:blood / Q000235:genetics* / Q000276:immunology*; D012334:RNA, Neoplasm / Q000097:blood / Q000235:genetics
chemical_list: D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D012334:RNA, Neoplasm; D002268:Carboxypeptidases; C473848:FOLH1 protein, human; D043425:Glutamate Carboxypeptidase II