The breast cancer patients with unsuspected metastasis found and treatment plan changed (C1) had lower proportion of the expression of ER (%) and PR (%) in tumor cells than the C0 group (ER: 10 [0–85] vs. 80 [15–90], p=0.026; PR: 1 [0–10] vs. 20 [0–70], p=0.041), as presented in Figure 2C. This evidence concerns the gene ESR1 and breast cancer.