To further explore the relationship between levels of estrogen and naphthalene-derived quinones protein adducts and disease status of breast cancer, we plotted the ratio of 1,2-NPQ-Alb to (1,2-NPQ-Alb plus 1,4-NPQ-Alb) versus the ratio of E2-3,4-Q-2-S-Alb to (E2-2,3-Q-4-S-Alb plus E2-3,4-Q-2-S-Alb) derived from breast cancer patients and controls (Fig. 4). Here, ALB is linked to breast cancer.