Quantitative analysis of tumor-derived methylated RUNX3 sequences in the serum of gastric cancer patients.
OBJECTIVE
Using real-time quantitative methylation-specific PCR (RTQ-MSP), methylated RUNX3 sequences were quantified and the fractional concentrations of circulating tumor DNA in serum were determined, along with peripheral blood cells collected preoperatively, intraoperatively and postoperatively from 65 patients with gastric cancer.


RESULTS
RTQ-MSP was sufficiently sensitive to detect RUNX3 methylation. Quantitative MSP data were expressed in terms of the methylation index, which was defined as the relative amount of methylated RUNX3 sequences divided by the concentration of methylated actin. High levels of methylated RUNX3 sequences were detected in the peripheral circulation of 29% (19 of 65) of the gastric cancer patients. The RUNX3 methylation index was concordant with cancer stage, histology, lymphatic and vascular invasion, and was more sensitive than carcinoembryonic antigen (CEA) as a biomarker. Twenty-nine percent (19 out of 65) of preoperative serum samples had methylated RUNX3 sequences, ranging from 5.2 to 1625955 (median quantity=43 m-index, sensitivity 95.5%, specificity 62.5%, AUC 0.8651). After surgical resection, the median RUNX3 methylation index in serum significantly decreased. These results demonstrate the clinical usefulness and effectiveness of peripheral blood RTQ-MSP for detecting and monitoring gastric cancer after treatment. Furthermore, 5 out of the 30 preoperative control samples of benign disease (cases of panperitonitis due to acute appendicitis or cholecystitis) showed transient RUNX3 methylation which decreased after the operation in accordance with recovery.


CONCLUSIONS
Quantification of epigenetic changes in serum RUNX3 methylation using RTQ-MSP is useful for the detection and monitoring of gastric cancer.
Sakakura
Chouhei
C
Department of Surgery and Regenerative Medicine, Division of Surgery and Oncology of Digestive System, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-dori, Kyoto 602-8566, Japan. sakakura@koto.kpu-m.ac.jp
Hamada
Takuo
T
Miyagawa
Koji
K
Nishio
Minoru
M
Miyashita
Atushi
A
Nagata
Hiroyuki
H
Ida
Hiroshi
H
Yazumi
Shujiro
S
Otsuji
Eigo
E
Chiba
Tsutomu
T
Ito
Kosei
K
Ito
Yoshiaki
Y
D001483:Base Sequence; D014408:Biomarkers, Tumor / Q000097:blood / Q000235:genetics*; D050677:Core Binding Factor Alpha 3 Subunit / Q000097:blood / Q000235:genetics*; D019175:DNA Methylation; D017931:DNA Primers; D042241:Early Diagnosis; D006801:Humans; D016133:Polymerase Chain Reaction; D012008:Recurrence; D013274:Stomach Neoplasms / Q000097:blood* / Q000175:diagnosis
D014408:Biomarkers, Tumor; D050677:Core Binding Factor Alpha 3 Subunit; D017931:DNA Primers; C493729:Runx3 protein, human