Blood and Saliva Collection for DNA Extraction

The collection of specimens has been described previously [32 (link)]. Briefly, cases and controls provided a blood sample and completed a brief questionnaire at the time of blood draw, which updated breast and reproductive and gynecologic history and several lifestyle factors. Women who declined providing blood provided saliva in Oragene DNA self-collection kits (DNA Genotek, Kanata, ON, Canada). All biological specimens were sent overnight to the UCI laboratory. DNA was extracted from blood clots using Qiagen Clotspin Baskets and DNA QIAmp DNA Blood Maxi Kits (Qiagen, Inc., Valencia, CA, USA) in accordance with Qiagen protocols. DNA was extracted from saliva samples using the Oragene protocol (DNA Genotek).