CYP1A2 and breast cancer: Although the CYP1A2 genotype alone did not affect breast cancer risk, the authors noted that, coffee consumption (≥2 cups per day) combined with the CYP1A2*1F A/A genotype is associated with a greater proportion of ER− tumors among patients with breast cancer in a population-based study (OR = 4.2; 95% CI, 1.9–9.3; P = 0.0002).