NUDT9 and breast cancer: In addition, ADP-ribose pyrophosphatase was determined to be causally associated with breast cancer as a protective factor (IVW, p=0.019, OR = 0.905, 95% CI: 0.833–0.983), while a causal relationship was established between [pyruvate dehydrogenase (acetyl-transferring)] kinase isozyme 1 and breast cancer as a risk factor (IVW, p=0.038, OR = 1.093, 95% CI: 1.005–1.189).