title: Epigenetic clustering of lung adenocarcinomas based on DNA methylation profiles in adjacent lung tissue: Its correlation with smoking history and chronic obstructive pulmonary disease.
abstract: The aim of this study was to clarify the significance of DNA methylation alterations during lung carcinogenesis. Infinium assay was performed using 139 paired samples of non-cancerous lung tissue (N) and tumorous tissue (T) from a learning cohort of patients with lung adenocarcinomas (LADCs). Fifty paired N and T samples from a validation cohort were also analyzed. DNA methylation alterations on 1,928 probes occurred in N samples relative to normal lung tissue from patients without primary lung tumors, and were inherited by, or strengthened in, T samples. Unsupervised hierarchical clustering using DNA methylation levels in N samples on all 26,447 probes subclustered patients into Cluster I (n = 32), Cluster II (n = 35) and Cluster III (n = 72). LADCs in Cluster I developed from the inflammatory background in chronic obstructive pulmonary disease (COPD) in heavy smokers and were locally invasive. Most patients in Cluster II were non-smokers and had a favorable outcome. LADCs in Cluster III developed in light smokers were most aggressive (frequently showing lymphatic and blood vessel invasion, lymph node metastasis and an advanced pathological stage), and had a poor outcome. DNA methylation levels of hallmark genes for each cluster, such as IRX2, HOXD8, SPARCL1, RGS5 and EI24, were again correlated with clinicopathological characteristics in the validation cohort. DNA methylation profiles reflecting carcinogenetic factors such as smoking and COPD appear to be established in non-cancerous lung tissue from patients with LADCs and may determine the aggressiveness of tumors developing in individual patients, and thus patient outcome.
authors.forename: Takashi
authors.initials: T
authors.lastname: Sato
authors.forename: Eri
authors.initials: E
authors.lastname: Arai
authors.forename: Takashi
authors.initials: T
authors.lastname: Kohno
authors.forename: Yoriko
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Sayaka
authors.initials: S
authors.lastname: Miyata
authors.forename: Koji
authors.initials: K
authors.lastname: Tsuta
authors.forename: Shun-ichi
authors.initials: S
authors.lastname: Watanabe
authors.forename: Kenzo
authors.initials: K
authors.lastname: Soejima
authors.forename: Tomoko
authors.initials: T
authors.lastname: Betsuyaku
authors.forename: Yae
authors.initials: Y
authors.lastname: Kanai
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics*; D000077192:Adenocarcinoma of Lung; D000328:Adult; D000368:Aged; D016000:Cluster Analysis; D019175:DNA Methylation / Q000235:genetics*; D044127:Epigenesis, Genetic / Q000235:genetics*; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000235:genetics*; D012907:Smoking / Q000009:adverse effects* / Q000235:genetics