p53 mutation–negative breast cancer was positively associated with detectable adducts (OR = 1.33; 95% CI, 1.02–1.73), active and passive smoking (OR = 1.55; 95% CI, 1.11–2.15), passive smoking from a spouse (OR = 1.25; 95% CI, 1.01–1.54), and high lifetime intake of grilled and smoked meat (OR = 1.51; 95% CI, 1.25–1.82). This evidence concerns the gene TP53 and breast cancer.