Research findings manifested that protein levels of CYP2U1 was dramatically higher in ER- in comparison with ER+ cancer tissues (P = 0.0173) (Figure 3B), while it was not reach statistical significance in the PR statue (P = 0.1586) (Figure 3C) and HER2 expression (P = 0.5602) (Figure 3D) of breast cancer patients. This evidence concerns the gene ESR1 and cancer.