anlotinib + letrozole + pyrotinib

A combination therapy consisting of three active ingredients: - **Pyrotinib**: An oral, irreversible pan-ErbB receptor tyrosine kinase inhibitor targeting EGFR (HER1), HER2, and HER4. It promotes cellular apoptosis and inhibits cancer cell proliferation by blocking the activation of downstream RAS/RAF/MEK/MAPK and PI3K/AKT signaling pathways. - **Anlotinib**: A multi-target tyrosine kinase inhibitor that primarily targets VEGFR, FGFR, PDGFR, and c-Kit, inhibiting angiogenesis and tumor growth. - **Letrozole**: An aromatase inhibitor that reduces estrogen production by blocking the enzyme aromatase, which converts anrogens to estrogens. It is primarily used in hormone receptor-positive breast cancer. This triple combination likely targets multiple cancer pathways simultaneously: HER2 signaling (pyrotinib), angiogenesis (anlotinib), and estrogen-dependent growth (letrozole).