ESR1 and breast cancer: We performed a Western blot analysis and found that treatment of MCF-7 cells with BC-N102 led to a time course-dependent downregulation of the ER, PI3K, p-ERK, p-Akt, p38 MAPK, CDK2, and CDK4 while increasing p38 MAPK expression in the MCF-7 cell line (Figure 4C).