Although Sorafenib is a kinase inhibitor with multiple targets including RTKs and RAF, its treatment did not affect the total tyrosyl phosphorylation and ERK phosphorylation in TamR cells (Figure S5), indicating that inhibition of TamR ER+ breast cancer cell growth by Sorafenib under the concentration used is not through inhibition of RTKs and RAF. This evidence concerns the gene ESR1 and breast cancer.