title: Decreased expression of repulsive guidance molecule member A by DNA             methylation in colorectal cancer is related to tumor progression.
abstract: Previous studies have shown decreased expression of repulsive guidance molecule             member A (RGMa) in colorectal cancer. However, the relationship between the expression             levels and promoter DNA methylation status of RGMa and the clinical characteristics             of colorectal cancer has not been previously reported. Here, we investigated the             expression of RGMa by immunohistochemistry, real-time PCR and western blotting             and analyzed the methylation status of the RGMa promoter using Sequenom's MassARRAY             platform in colorectal cancer tissues and adjacent normal colorectal tissues.             The results showed that RGMa expression was decreased in cancer tissues compared             with adjacent normal tissues (p<0.01). Furthermore, a tendency for decreased             expression in tumor tissues was observed from Dukes' stage A to stage D (p<0.01).             In addition, significantly higher levels of hypermethylation in promoter regions             of RGMa were observed in colorectal cancer tissues, compared with those in adjacent             normal colorectal tissues (p<0.01). Moreover, the methylation levels of RGMa             in tumor tissues were significantly increased in Dukes' stage C and D compared             with Dukes' stage A and B (p<0.01). Our results indicate that RGMa expression             and promoter methylation status are closely related to colorectal cancer genesis             and progression. Determination of the expression level and methylation frequency             of RGMa in colorectal cancer tissues may have benefit for early diagnosis and             for evaluating patient prognosis.
authors.affiliation: Department of Human Anatomy, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu 610041, Sichuan Province, PR China.
authors.forename: Zhi-Wei
authors.initials: ZW
authors.lastname: Zhao
authors.forename: Wen-Jing
authors.initials: WJ
authors.lastname: Lian
authors.forename: Guo-Qing
authors.initials: GQ
authors.lastname: Chen
authors.forename: Hong-Ying
authors.initials: HY
authors.lastname: Zhou
authors.forename: Gui-Ming
authors.initials: GM
authors.lastname: Wang
authors.forename: Xia
authors.initials: X
authors.lastname: Cao
authors.forename: Hui-Jun
authors.initials: HJ
authors.lastname: Yang
authors.forename: Yi-Ping
authors.initials: YP
authors.lastname: Hou
mesh_terms: D000328:Adult; D000368:Aged; D001483:Base Sequence; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology*; D019175:DNA Methylation; D018450:Disease Progression; D044127:Epigenesis, Genetic; D005260:Female; D058851:GPI-Linked Proteins / Q000235:genetics / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic
chemical_list: D058851:GPI-Linked Proteins; D009419:Nerve Tissue Proteins; C522183:RGMA protein, human