Detection of circulating prostate tumor cells: alternative spliced variant of PSM induced false-positive result.
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.
Hisatomi
Hisashi
H
Center for Molecular Biology and Cytogenetics, SRL, Inc, Hino, Tokyo, Japan. hisatomi@srl.srl-inc.co.jp
Nagao
Kumi
K
Kawakita
Mutsuji
M
Matsuda
Tadashi
T
Hirata
Hiroyuki
H
Yamamoto
Shigeki
S
Nakamoto
Takaaki
T
Harasawa
Hiroshi
H
Kaneko
Noboru
N
Hikiji
Kazumasa
K
Tsukada
Yutaka
Y
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
D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D012334:RNA, Neoplasm; D002268:Carboxypeptidases; C473848:FOLH1 protein, human; D043425:Glutamate Carboxypeptidase II