Table 3.

Characteristics of studies investigating the association between global DNA methylation and breast cancer risk (n = 12)

Prospective studies (n = 5)
StudyCountryStudy designStudy populationSample size (cases/controls)Age (years)aBlood timingMethylation assayMethylation measureTissue
Brennan (2012; ref. 42)United KingdomNested case–controlBGS242/24154/54N/RPyrosequencingLINE1WBC
ItalyEPIC263/23252/52
Australia and New ZealandKConFab218/15350/60
Deroo (2014; ref. 43)USA and Puerto RicoCase–cohortSister study294/646<601.3 years avgPyrosequencingLINE1Whole blood
Severi (2014; ref. 44)AustraliaNested case–controlMCCS420/42064/6450% > 8.9 yearsIllumina 450kBetasWhole blood
van Veldhoven (2015; ref. 45)ItalyNested case–controlEPIC166/16654.4/54.250% > 3.8 yearsIllumina 450kBetasWBC
NorwayNOWAC192/19255.4/55.450% > 2.1 yearsIllumina 450k
United KingdomBGS548/54852.0/52.0N/RWGBS
Sturgeon (2017; ref. 46)USANested case–controlPLCO (control arm of intervention study)428/41960+68.6% > = 4 years%5-mdCGlobalWBC
Nonprospective studies (n = 7)
StudyCountryStudy designStudy populationSample size (cases/controls)Age (years) aBlood timingMethylation assayMethylation measureTissue
Choi (2009; ref. 47)USAFamily-based case–controlAmerican women176/173< 60At diagnosis5-mdCGlobalWBC
Cho (2010; ref. 48)TurkeyCase–controlTurkish women40/4050.8/48.3At diagnosisMethylLight (%)LINE1WBC
ALU
SAT2
Wu (2012; ref. 49)USAFamily-based case–controlSisters discordant for breast cancer266/33449.5/48.0At diagnosisMethylLight (%)LINE1WBC
ALU
SAT2
Xu (2012; ref. 50)USAPopulation based case–controlAmerican women (LIBCSP)1064/110160+At diagnosisLUMA (% methylation)LUMAWBC
PyrosequencingLINE1
Kitkumthorn (2012; ref. 51)ThailandPopulation-based case–controlWomen from Thailand36/14450.28/47.72At diagnosisCOBRA (%)LINE1WBC
Delgado-Cruzata (2012; ref. 52)USAFamily-based case–controlSisters discordant for breast cancer263/32149.6/48.2At diagnosisLUMA (% methylation)LUMAWBC
3H-methylGlobal
Kuchiba (2014; ref. 53)JapanHospital-based case–controlJapanese women384/38453.9/54.1At diagnosisLUMA (% methylation)LUMAWBC
  • aAverage age for cases/controls if available and age range if not available.