title: Distinct profiles of epigenetic evolution between colorectal cancers with and without metastasis.
abstract: Liver metastasis is a fatal step in the progression of colorectal cancer (CRC); however, the epigenetic evolution of this process is largely unknown. To decipher the epigenetic alterations during the development of liver metastasis, the DNA methylation status of 12 genes, including 5 classical CpG island methylator phenotype (CIMP) markers, was analyzed in 62 liver metastases and in 78 primary CRCs (53 stage I-III; 25 stage IV). Genome-wide methylation analysis was also performed in stage I-III CRCs and in paired primary and liver metastatic cancers. Methylation frequencies of MGMT and TIMP3 increased progressively from stage I-III CRCs to liver metastasis (P = 0.043 and P = 0.028, respectively). The CIMP-positive cases showed significantly earlier recurrence of disease than did CIMP-negative cases with liver metastasis (P = 0.030), whereas no such difference was found in stage I-III CRCs. Genome-wide analysis revealed that more genes were methylated in stage I-III CRCs than in paired stage IV samples (P = 0.008). Hierarchical cluster analysis showed that stage I-III CRCs and stage IV CRCs were clustered into two distinct subgroups, whereas most paired primary and metastatic cancers showed similar methylation profiles. This analysis revealed distinct methylation profiles between stage I-III CRCs and stage IV CRCs, which may reflect differences in epigenetic evolution during progression of the disease. In addition, most methylation status in stage IV CRCs seems to be established before metastasis.
authors.affiliation: Division of Molecular Oncology, Aichi Cancer Center Research Institute, Nagoya, Japan.
authors.forename: Hai-Xing
authors.initials: HX
authors.lastname: Ju
authors.forename: Byonggu
authors.initials: B
authors.lastname: An
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Okamoto
authors.forename: Keiko
authors.initials: K
authors.lastname: Shinjo
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Kanemitsu
authors.forename: Koji
authors.initials: K
authors.lastname: Komori
authors.forename: Takashi
authors.initials: T
authors.lastname: Hirai
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Shimizu
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Sano
authors.forename: Akira
authors.initials: A
authors.lastname: Sawaki
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tajika
authors.forename: Kenji
authors.initials: K
authors.lastname: Yamao
authors.forename: Makiko
authors.initials: M
authors.lastname: Fujii
authors.forename: Hideki
authors.initials: H
authors.lastname: Murakami
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Osada
authors.forename: Hidemi
authors.initials: H
authors.lastname: Ito
authors.forename: Ichiro
authors.initials: I
authors.lastname: Takeuchi
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Sekido
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kondo
mesh_terms: D000368:Aged; D016000:Cluster Analysis; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D019143:Evolution, Molecular; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D008957:Models, Genetic; D009362:Neoplasm Metastasis; D010641:Phenotype; D013997:Time Factors