title: Reduced expression of PER3 is associated with incidence and development of colon cancer.
abstract: BACKGROUND
  Period 3 (PER3), a circadian regulation protein, influences cell cycle, growth, and differentiation. The aim of the present study was to determine whether PER3 expression is associated with colon cancer incidence and progression.
  
  
  METHODS
  PER3 expression was analyzed in the normal and cancerous tissues from patients with colon cancer by establishing a long serial analysis of gene expression (SAGE) database as well as by real-time PCR and immunohistochemistry.
  
  
  RESULTS
  As compared with normal tissue, a 2.8-fold decrease in PER3 mRNA levels in colon cancerous tissue was observed. Real-time PCR analysis revealed that PER3 mRNA levels in tumor tissues were lower than in normal tissues (P < 0.001) in both patients with colon tumor and those with rectal tumor. In addition, PER3 expression was related to multiple clinicopathologic factors, including tumor location, differentiation, and stage. Furthermore, the incidence of death was higher in subjects with PER3-negative tumors (P = 0.025); the estimated overall survival time was 71.5 ± 2.2 months and 58.6 ± 5.0 months in subjects with PER3-positive and PER3-negative tumors, respectively (P = 0.020).
  
  
  CONCLUSIONS
  PER3 may play a role in colon cancer progression.
authors.affiliation: Department of General Surgery, Shanghai Jiao Tong University Affiliated First People's Hospital, Shanghai, China.
authors.forename: Xiaoliang
authors.initials: X
authors.lastname: Wang
authors.forename: Dongwang
authors.initials: D
authors.lastname: Yan
authors.forename: Mujian
authors.initials: M
authors.lastname: Teng
authors.forename: Junwei
authors.initials: J
authors.lastname: Fan
authors.forename: Chongzhi
authors.initials: C
authors.lastname: Zhou
authors.forename: Dawei
authors.initials: D
authors.lastname: Li
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Qiu
authors.forename: Xing
authors.initials: X
authors.lastname: Sun
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.forename: Tonghai
authors.initials: T
authors.lastname: Xing
authors.forename: Huamei
authors.initials: H
authors.lastname: Tang
authors.forename: Xiao
authors.initials: X
authors.lastname: Peng
authors.forename: Zhihai
authors.initials: Z
authors.lastname: Peng
mesh_terms: D000368:Aged; D002277:Carcinoma / Q000235:genetics* / Q000378:metabolism; D003106:Colon / Q000378:metabolism*; D003110:Colonic Neoplasms / Q000235:genetics* / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D056950:Period Circadian Proteins / Q000235:genetics* / Q000378:metabolism; D016016:Proportional Hazards Models; D012333:RNA, Messenger / Q000378:metabolism; D018709:Statistics, Nonparametric
chemical_list: C512644:PER3 protein, human; D056950:Period Circadian Proteins; D012333:RNA, Messenger