Identification of hormone receptors and HER-2 in samples of mediastinal nodal metastases of breast carcinoma obtained through endobronchial ultrasound

Aim : The expression of estrogen receptor (ER) and progesterone receptor (PR) in samples of metastatic breast carcinoma can differ from the primary tumor in 20% of cases. The absence of receptors and the presence of HER2 protooncogene is associated with resistance to tamoxifen. The aim of this study is to determine the ability of the samples of mediastinal nodal metastases of breast carcinoma obtained by endobronchial ultrasound (EBUS) for the identification of ER, PR and HER2. Patients and method: We prospectively included patients with a final diagnosis of breast cancer with mediastinal nodal metastases diagnosed by EBUS. The determination of hormone receptors was performed by immunohistochemistry using antibody 6F11 antireceptor estrogen and progesterone antireceptor antibody 5D10. The reference threshold to establish a positive result was placed in a 1% of tumor cells. HER2 staining was determined by Herceptest and positive cases were confirmed by fluorescence in situ hybridization. Results: Fourteen patients were included. Estrogen receptors could be identified in 12 (85.7%) cases, progesterone receptors in 8 (57.1%) and HER2 in 8 (57.1%). In 5 cases there were no information about the primary tumor status and thereby changes in the status of PE, RE and HER2 could not be assessed. Of the remaining 7 patients, only one (14.2%) case showed a change (negativisation) in a progesterone receptor. Conclusion: Samples of mediastinal nodal metastases of breast carcinoma obtained through EBUS are suitable for the identification of hormone receptors and HER2.