Comparison of methylation-specific polymerase chain reaction (MSP) with reverse transcriptase-polymerase chain reaction (RT-PCR) in peripheral blood of gastric cancer patients.
OBJECTIVE
To achieve a complete cure in gastric cancer, primary and recurrent tumors must be detected at an early stage. This study was designed to compare carcinoembryonic antigen (CEA)-specific reverse transcriptase-polymerase chain reaction (RT-PCR) and methylation-specific polymerase chain reaction (MSP) for p16, E-cadherin, and retinoic acid receptor beta (RARbeta) genes using blood samples from gastric cancer patients.


METHODS
Preoperative blood samples obtained from 41 patients with gastric cancer, including 9 with early-stage disease, and were subjected to RT-PCR and MSP assays.


RESULTS
Ten of 41 (24%) patients exhibited a CEA-specific signal by RT-PCR. Positive rates were 11, 13, 50, and 50% in stages I, II, III, and IV, respectively. A significant association was found between RT-PCR results and stage (P< 0.01). The MSP assay detected hypermethylation of p16 in 9 patients (22%), E-cadherin in 9 patients (22%), and RARbeta in 6 patients (15%). Altogether, 18 patients (44%) showed hypermethylation. The positive rates were 37, 50, 40, and 75% in stages I, II, III, and IV, respectively. A significant association was found between aberrant methylation and venous invasion (P< 0.05). Neither the CEA-specific signal nor hypermethylation was detected in serum from control volunteers.


CONCLUSIONS
The detection rate of MSP was higher than that of RT-PCR in gastric cancer. Both assays can serve as markers that allow selection of those cases requiring more intensive screening and aggressive postoperative treatment.
Koike
Hiroshi
H
Department of Digestive Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Ichikawa
Daisuke
D
Ikoma
Hisashi
H
Otsuji
Eigo
E
Kitamura
Kazuya
K
Yamagishi
Hisakazu
H
D000230:Adenocarcinoma / Q000097:blood / Q000378:metabolism / Q000473:pathology*; D000368:Aged; D015820:Cadherins / Q000235:genetics; D002272:Carcinoembryonic Antigen / Q000096:biosynthesis* / Q000235:genetics; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics; D019175:DNA Methylation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D018168:Receptors, Retinoic Acid / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000097:blood / Q000378:metabolism / Q000473:pathology*
D015820:Cadherins; D002272:Carcinoembryonic Antigen; D019941:Cyclin-Dependent Kinase Inhibitor p16; D012333:RNA, Messenger; D018168:Receptors, Retinoic Acid; C082925:retinoic acid receptor beta