Tyrosine phosphorylated STAT3 was also significantly reduced in secondary tumors in vivo that originated in wildtype recipient females from the transplantation of MMTV-Flp FSF-KrasG12D Rosa26CAG-FSF-CreERT2 Jak1fl/fl mammary tumor cells and treatment with Tam (Fig. 7D). Here, STAT3 is linked to breast cancer.