title: Methylation status of theAPCandRASSF1Apromoter in cell-free circulating DNA and its prognostic role in patients with colorectal cancer.
abstract: DNA methylation is the most frequent epigenetic alteration. Using methylation-specific polymerase chain reaction (MSP), the methylation status of the adenomatous polyposis coli (APC) and Ras association domain family 1 isoform A (RASSF1A) genes was examined in cell-free circulating DNA from 155 plasma samples obtained from patients with early and advanced colorectal cancer (CRC).APCandRASSF1Ahypermethylation was frequently observed in both early and advanced disease, and was significantly associated with a poorer disease outcome. The methylation status of theAPCandRASSF1Apromoters was investigated in cell-free DNA of patients with CRC. Using MSP, the promoter methylation status ofAPCandRASSF1Awas examined in 155 blood samples obtained from patients with CRC, 88 of whom had operable CRC (oCRC) and 67 had metastatic CRC (mCRC). The frequency ofAPCmethylation in patients with oCRC was 33%. MethylatedAPCpromoter was significantly associated with older age (P=0.012), higher stage (P=0.014) and methylatedRASSF1Astatus (P=0.050). The frequency ofAPCmethylation in patients with mCRC was 53.7%. In these patients,APCmethylation was significantly associated with methylatedRASSF1Astatus (P=0.016). The frequency ofRASSF1Amethylation in patients with oCRC was 25%. MethylatedRASSF1Ain oCRC was significantly associated with higher stage (P=0.021). The frequency ofRASSF1Amethylation in mCRC was 44.8%. MethylatedRASSF1Ain mCRC was associated with moderate differentiation (P=0.012), high levels of carcinoembryonic antigen (P=0.023) and methylatedAPCstatus (P=0.016). Patients with an unmethylatedAPCgene had better survival in both early (81±5 vs. 27±4 months, P<0.001) and advanced disease (37±7 vs. 15±3 months, P<0.001), compared with patients with methylatedAPC. Patients with an unmethylatedRASSF1Agene had better survival in both early (71±6 vs. 46±8 months, P<0.001) and advanced disease (28±4 vs. 16±3 months, P<0.001) than patients with methylatedRASSF1A. The observed significant correlations betweenAPCandRASSF1Apromoter methylation status and survival may be indicative of a prognostic role for these genes in CRC, which requires additional testing in larger studies.
authors.affiliation: Department of Medical Oncology, Medical School, Democritus University of Thrace, University General Hospital of Alexandroupolis, Alexandroupolis 68100, Greece.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Matthaios
authors.affiliation: Department of Medical Oncology, Medical School, Democritus University of Thrace, University General Hospital of Alexandroupolis, Alexandroupolis 68100, Greece.
authors.forename: Ioanna
authors.initials: I
authors.lastname: Balgkouranidou
authors.affiliation: Second Department of Surgery, Medical School, Democritus University of Thrace, University General Hospital of Alexandroupolis, Alexandroupolis 68100, Greece.
authors.forename: Anastasios
authors.initials: A
authors.lastname: Karayiannakis
authors.affiliation: Second Department of Surgery, Medical School, Democritus University of Thrace, University General Hospital of Alexandroupolis, Alexandroupolis 68100, Greece.
authors.forename: Helen
authors.initials: H
authors.lastname: Bolanaki
authors.affiliation: Department of Medical Oncology, Medical School, Democritus University of Thrace, University General Hospital of Alexandroupolis, Alexandroupolis 68100, Greece.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Xenidis
authors.affiliation: Department of Medical Oncology, Medical School, Democritus University of Thrace, University General Hospital of Alexandroupolis, Alexandroupolis 68100, Greece.
authors.forename: Kyriakos
authors.initials: K
authors.lastname: Amarantidis
authors.affiliation: Department of Medical Oncology, Medical School, Democritus University of Thrace, University General Hospital of Alexandroupolis, Alexandroupolis 68100, Greece.
authors.forename: Leonidas
authors.initials: L
authors.lastname: Chelis
authors.affiliation: Second Department of Surgery, Medical School, Democritus University of Thrace, University General Hospital of Alexandroupolis, Alexandroupolis 68100, Greece.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Romanidis
authors.affiliation: Laboratory of Pharmacology, Medical School, Democritus University of Thrace, University General Hospital of Alexandroupolis, Alexandroupolis 68100, Greece.
authors.forename: Aikaterini
authors.initials: A
authors.lastname: Chatzaki
authors.affiliation: Laboratory of Analytical Chemistry, Department of Chemistry, University of Athens, Athens 15771, Greece.
authors.forename: Evi
authors.initials: E
authors.lastname: Lianidou
authors.affiliation: Laboratory of Statistics, Medical School, Democritus University of Thrace, University General Hospital of Alexandroupolis, Alexandroupolis 68100, Greece.
authors.forename: Grigorios
authors.initials: G
authors.lastname: Trypsianis
authors.affiliation: Department of Medical Oncology, Medical School, Democritus University of Thrace, University General Hospital of Alexandroupolis, Alexandroupolis 68100, Greece.
authors.forename: Stylianos
authors.initials: S
authors.lastname: Kakolyris
keywords: APC; DNA methylation; RASSF1A; cell-free DNA; colon cancer