ESR1 and neoplasm: There were no statistical differences between the regression groups in terms of mean proportion of ER positive tumor cells (43.75 ± 11.18, 30.55 ± 9.09, and 27.56 ± 9.54, respectively), PR positive tumor cells (31.25 ± 10.28, 20.83 ± 7.73, and 19.4 ± 8.80, respectively) and expression of Ki67 (50.63 ± 5.95, 54.69 ± 5.64, and 53.21 ± 7.33, respectively) (Figure 2).