title: Case-control study of breast cancer in India: Role of PERIOD3 clock gene length polymorphism and chronotype.
abstract: BACKGROUND
  This study examined a PERIOD3 (PER3) gene variable number tandem repeat polymorphism and chronotype as potential BrCA risk factors among Indian women.
  
  
  METHODS
  This case-control study included sporadic, histologically confirmed BrCA cases (n = 255) and controls (n = 249) from India with data collection from 2010-2012.
  
  
  RESULTS
  Women with the 4/5 or 5/5 PER3 genotype had a nonstatistically significant 33% increased odds of BrCA. Cases were more likely to have a morning (OR = 2.43, 95% CI = 1.23-4.81) or evening (OR = 2.55, 95% CI = 1.19-5.47) chronotype.
  
  
  CONCLUSIONS
  Findings are consistent with the possibility that extremes in chronotype may elicit circadian desynchronization, resulting in increased BrCA susceptibility.
authors.affiliation: South Carolina Statewide Cancer Prevention and Control Program,1.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Wirth
authors.forename: James B
authors.initials: JB
authors.lastname: Burch
authors.forename: James R
authors.initials: JR
authors.lastname: Hébert
authors.forename: Pradnya
authors.initials: P
authors.lastname: Kowtal
authors.forename: Aparna
authors.initials: A
authors.lastname: Mehrotra-Kapoor
authors.forename: Susan E
authors.initials: SE
authors.lastname: Steck
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Hurley
authors.forename: Prakash C
authors.initials: PC
authors.lastname: Gupta
authors.forename: Mangesh S
authors.initials: MS
authors.lastname: Pednekar
authors.forename: Shawn D
authors.initials: SD
authors.lastname: Youngstedt
authors.forename: Hongmei
authors.initials: H
authors.lastname: Zhang
authors.forename: Rajiv
authors.initials: R
authors.lastname: Sarin
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology / Q000235:genetics*; D016022:Case-Control Studies; D002940:Circadian Rhythm / Q000235:genetics*; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D008875:Middle Aged; D009687:Nuclear Proteins / Q000235:genetics; D056950:Period Circadian Proteins / Q000235:genetics*; D011110:Polymorphism, Genetic; D012307:Risk Factors; D011795:Surveys and Questionnaires; D020080:Tandem Repeat Sequences / Q000235:genetics
chemical_list: D009687:Nuclear Proteins; C512644:PER3 protein, human; D056950:Period Circadian Proteins
keywords: Breast Cancer; Circadian; Clock Gene; Diurnal Preference