Bone metastases were often the first distant metastasis site when the tumor expressed SNAI1 or ER (87 (60.0%) of the 145 patients with SNAI1-positive tumor were first diagnosed with bone metastases as compared with 29 (42.0%) of the 69 women with SNAI1-negative tumor, P = 0.014; similarly, 85 (59.9%) of the 142 women with ER-positive cancer compared with 42 (46.7%) of the 90 women with ER-negative tumor had the first distant metastases in the bone, P = 0.049, Table 3). Here, ESR1 is linked to cancer.