GP5 and breast cancer: Relative to patients aged 50 to 59 years, those diagnosed with breast cancer at younger than 40 years had a 6.8-fold increased likelihood of carrying a GPV in B1B2P2 (OR, 6.83; 95% CI, 2.22-20.90), and compared with patients with no family history of cancer, those with a family history of ovarian cancer had a nearly 10-fold increased odds (OR, 9.75; 95% CI, 2.65-35.85).