title: Detailed methylation patterns and protein expression profiles of MGMT in colorectal carcinoma surgical margins.
abstract: OBJECTIVE
  Molecular margin analysis is considered more sensitive in detecting preneoplastic lesions and residual cancer cells than conventional histological margin examination. Hence, we examined MGMT expression profile and methylation status in histologically negative margins of colorectal cancer patients.
  
  
  METHODS
  This study included 24 colorectal tumor tissues and corresponding negative surgical margin tissues. MGMT promoter methylation patterns were analyzed by using methylation-specific oligonucleotide microarray. In addition, MGMT protein expression was analyzed by immunohistochemistry. MGMT clinical significance was evaluated together with other well-known clinicopathological factors.
  
  
  RESULTS
  Extensive MGMT promoter methylation was observed in tumor tissues; a moderate methylation level was found in surgical margin tissues and little or no methylation was observed in the normal control. There was a trend towards longer overall survival for those patients with negative MGMT immunostaining in surgical margins.
  
  
  CONCLUSIONS
  MGMT expression negative in surgical margin tissues indicates longer overall survival for colorectal tumor patients.
authors.affiliation: State Key Laboratory of Bioelectronics, Southeast University, Nanjing 210096, China.
authors.forename: Dingdong
authors.initials: D
authors.lastname: Zhang
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Bai
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Junfeng
authors.initials: J
authors.lastname: Luo
authors.forename: Qinyu
authors.initials: Q
authors.lastname: Ge
authors.forename: Yingjuan
authors.initials: Y
authors.lastname: Qiao
authors.forename: Chao
authors.initials: C
authors.lastname: Jia
authors.forename: Zuhong
authors.initials: Z
authors.lastname: Lu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001483:Base Sequence; D001706:Biopsy / Q000379:methods; D002277:Carcinoma / Q000235:genetics* / Q000378:metabolism / Q000401:mortality / Q000601:surgery; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000401:mortality / Q000601:surgery; D019175:DNA Methylation; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D019853:O(6)-Methylguanine-DNA Methyltransferase / Q000235:genetics* / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D016019:Survival Analysis
chemical_list: D019853:O(6)-Methylguanine-DNA Methyltransferase