In a prospective cohort study by Odén et al., the authors showed that high vs. low plasma OPG was associated with risk of developing breast cancer among BRCA1 and BRCA2 mutation carriers (n = 206; HR = 0.25; 95% CI 0.08–0.78; p = 0.02) [44]. The gene discussed is BRCA2; the disease is breast cancer.