Among them, XBP1 had a genetically promoted incidence for both AF (OR = 1.07, 95% CI, 1.03–1.11, Pfdr = 0.004, PPH3+PPH4 = 0.90) and breast cancer (OR = 1.11,95%CI, 1.08–1.14, Pfdr = 2.41 × 10−8, PPH3+PPH4 = 1.00), NAGLU had a pro-incidence effect on AF (OR = 1.16,95%CI, 1.07–1.27, Pfdr = 0.005, PPH3+PPH4 = 0.81) and a protective effect on breast cancer (OR = 0.82,95%CI, 0.76–0.89, Pfdr = 0.001, PPH3+PPH4 = 1.00). Here, XBP1 is linked to breast carcinoma.