title: Aberrant methylation and silencing ofIRF8expression in non-small cell lung cancer.
abstract: The aim of the present study was to investigate the aberrant methylation and altered expression of the interferon regulatory factor 8 (IRF8) gene in non-small cell lung cancer (NSCLC). Pyrosequencing assays were performed on 191 tumor specimens from NSCLC patients. The changes inIRF8mRNA expression, prior to and following treatment with a demethylating agent and methylation itself, were examined in 13 lung cancer cell lines by quantitative polymerase chain reaction (qPCR) and pyrosequencing. IRF8 protein expression was examined in 94 of the 191 NSCLC specimens by immunohistochemical analysis. TheIRF8methylation level was significantly higher in the tumor tissues than in matched non-malignant lung tissues (P<0.0001).IRF8was more frequently methylated in tumor tissues compared with matched non-malignant lung tissues, as defined by a predetermined cut-off value (P<0.0001). TheIRF8methylation level was strongly correlated with the change in mRNA expression in lung cancer cell lines and with the protein expression level in primary tumors. TheIRF8gene was more frequently methylated in patients without an epidermal growth factor receptor (EGFR) mutation than in patients with an EGFR mutation (P=0.015).IRF8methylation correlated with recurrent prognosis in adenocarcinomas (log-rank test, P=0.048). IRF8 protein expression was frequently silenced in males, smokers, patients with non-adenocarcinoma or with wild-type EGFR, or in an advanced stage.IRF8is often silenced by its methylation, which is a frequent event in NSCLC and, therefore, methylation ofIRF8may act as a prognostic marker for recurrence. Analysis ofIRF8methylation status may provide novel opportunities for improved prognosis and therapy of resected NSCLC.
authors.affiliation: Department of Thoracic Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: Department of Thoracic Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan.
authors.forename: Koei
authors.initials: K
authors.lastname: Ikeda
authors.affiliation: Department of Thoracic Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Shiraishi
authors.affiliation: Department of Thoracic Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan.
authors.forename: Ayami
authors.initials: A
authors.lastname: Eguchi
authors.affiliation: Department of Thoracic Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Mori
authors.affiliation: Department of Thoracic Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yoshimoto
authors.affiliation: Department of Thoracic Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan.
authors.forename: Hidekatsu
authors.initials: H
authors.lastname: Shibata
authors.affiliation: Department of Pathology and Experimental Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Ito
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Baba
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Baba
keywords: IRF8; expression; methylation; pyrosequencing