title: Comparison of methylation-specific polymerase chain reaction (MSP) with reverse transcriptase-polymerase chain reaction (RT-PCR) in peripheral blood of gastric cancer patients.
abstract: 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.
authors.affiliation: Department of Digestive Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Koike
authors.forename: Daisuke
authors.initials: D
authors.lastname: Ichikawa
authors.forename: Hisashi
authors.initials: H
authors.lastname: Ikoma
authors.forename: Eigo
authors.initials: E
authors.lastname: Otsuji
authors.forename: Kazuya
authors.initials: K
authors.lastname: Kitamura
authors.forename: Hisakazu
authors.initials: H
authors.lastname: Yamagishi
mesh_terms: 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*
chemical_list: D015820:Cadherins; D002272:Carcinoembryonic Antigen; D019941:Cyclin-Dependent Kinase Inhibitor p16; D012333:RNA, Messenger; D018168:Receptors, Retinoic Acid; C082925:retinoic acid receptor beta