To investigate variation in tumor-driving signaling pathway activity within primary breast cancer tumors and between matched primary tumor and LN and DS metastases, activity of the PI3K growth factor pathway, the ER and AR hormonal pathways, and the developmental Wnt, HH and TGFβ pathways was measured at multiple locations in PT as well as in metastatic samples. The gene discussed is ESR1; the disease is neoplasm.