In addition, in the cohort study within the UK General Practice Research Database, it was found that metformin monotherapy had weaker association with breast cancer risk with a hazard ratio of 1.04 (95% CI: 0.79–1.37) as compared to sulfonylurea and insulin where the latter were more associated with breast cancer risk (HR: 1.33; 95% CI: 0.63–2.83) [30]. The gene discussed is INS; the disease is breast cancer.