Further studies are warranted to confirm our findings and clarify the interplay between HER2 and estrogen receptor pathways in HER2-positive (mbc) patients.
HER2 genomic amplification in circulating tumor DNA and estrogen receptor positivity predict primary resistance to trastuzumab emtansine (T-DM1) in patients with HER2-positive metastatic breast cancer.
We reviewed 91 patients with HER2-positive MBC treated with trastuzumab and investigated correlations between survival and clinical response to first trastuzumab-based therapy and biological markers, time to first tumor progression (1st TTP), response rate (RR), estrogen receptor (ER), Ki-67, and p53 overexpression.
A feasible approach for women with less aggressive, estrogen receptor/HER2-positive metastatic breast cancer is to consider trastuzumab (Herceptin; F. Hoffmann-La Roche, Basel, Switzerland) combined with endocrine therapy.