CGEMS Breast Cancer GWAS

The initial stage of the Cancer Genetic Markers of Susceptibility (CGEMS) breast cancer genome-wide association study (GWAS) included genotyping 528,173 SNPs (Illumina HumanHap550) in 1,145 postmenopausal women of European ancestry with invasive breast cancer and 1,142 controls from the Nurses' Health Study (NHS). Subsequently, incident invasive breast cancer cases from the Nurses' Health Study 2 (NHS2) cohort were genotyped using the Illumina HumanHap 610 quad. The NHS2 cases are younger than the cases in the first stage of the CGEMS breast cancer GWAS, which only included postmenopausal women. The NHS2 cases are a mix of pre- and postmenopausal women]]>
Cancer Genetic Markers of Susceptibility (CGEMS) Breast Cancer Genome-Wide Association ScanAll NHS1 study participants who were menopausal at blood draw with a confirmed diagnosis of invasive breast cancer and had sufficient stored blood available for DNA extraction at the time of case and control selection were included as cases in the CGEMS project. Controls were matched to cases based on age, blood collection variables (time, date, and year of blood collection, as well as recent (< months) use of postmenopausal hormones), ethnicity (all cases and controls are self-reported Caucasians), and menopausal status (all cases and controls were menopausal at blood draw). All NHS2 cases had a confirmed diagnosis of invasive breast cancer after baseline blood draw (taken between 1996 and 1999) but before sample selection in May 2004. All had sufficient stored blood available for DNA extraction. There were no other exclusion criteria. Specifically: there were no exclusions due to age or menopausal status at diagnosis.]]>
The Nurses' Health Study (NHS) is a longitudinal study of 121,700 women enrolled in 1976. The CGEMS case-control study is derived from 32,826 participants who provided a blood sample between 1989 and 1990 and were free of diagnosed breast cancer at blood collection and followed for incident disease until May 2004. The Nurses' Health Study 2 (NHS2) is a longitudinal study of 116,686 women enrolled in 1989. The CGEMS sample is derived from 29,611 participants who provided a blood sample between 1996 and 1999 and were free of diagnosed breast cancer at blood collection and followed for incident disease until May 2004. Cancer follow-up in the NHS and NHS 2 was conducted by personal mailings and searches of the National Death Index. It is estimated that the percentage of true cancers captured by this system is greater than 90%. Permission was requested from all participants diagnosed with cancer to review medical records to confirm the diagnoses and obtain additional information on tumor histology, staging, and other characteristics.]]>