Purpose: The aim of this study was to determine whether estrogen receptor (ER)/progesterone receptor (PR) and human epidermal growth factor receptor type 2 (HER2) statuses between primary tumors and paired liver metastatic localizations of breast carcinoma were modified by treatment or during the natural metastatic process.
Methods: ER, PR, and HER2 expressions were analyzed on paired tissue specimens taken from the primary and the liver metastatic tumors in breast cancer patients. The first group included 46 women who presented with T1-T4, N0-N3, M0 breast carcinoma when first diagnosed and were treated by neoadjuvant therapy or directly underwent surgery, then received postoperative treatment and developed liver metastasis several months/years later. The second group included 12 patients with liver metastatic breast carcinoma when first diagnosed for breast cancer. HER2 status was determined by immunohistochemistry as well as fluorescence in situ hybridization.
Results: Among the 46 patients in the first group, the ER/PR and HER2 statuses (when considered as a whole histological subtype) were changed between primary tumor and liver metastatic lesions in 12 patients (26.1%). While ER and PR status were modified in 14 (30.4%) and 25 (54.3%) patients, respectively, there were only 5 (10.9%) cases showed a discrepancy in the HER2 status. In the second group, the ER/PR and HER2 statuses (when considered as a whole subtype) were consistent between primary and liver metastatic tumor in 10 of 12 (83.3%) patients. ER, PR, and HER2 statuses were modified in 0 of 12 (0%), 4 of 12 (33.3%), and 1 of 12 (8.3%) cases, respectively.
Conclusions: ER/PR and HER2 statuses between primary and liver metastatic lesions of breast carcinoma can be modified after treatment but are stable in most cases during the natural metastatic process.