Estrogen, progesterone, and her-2eu receptor expression discrepancy in primary tumors and in-breast relapse in patients with breast cancer

摘要

To the Editor:Estrogen and progesterone receptors have increasing importance in the management of breast malignancy. 60-70% of primary breast tumors are ER and PR positive. This results in a good prognosis for the patients (1) and allows the use of endocrine therapy which is now a standard in the adjuvant treatment of hormone receptor-positive invasive breast cancers. The hormone receptors are determined by immunohisto-chemistry on paraffin sections. Her-2eu is a trans-membrane tyrosine kinase receptor which belongs to the family of the EGFR. The most common reason of Her-2eu overexpression in breast cancer is an amplification of the erbB2 gene. This results in a poor prognosis and occurs in 15-25% of all invasive breast cancers (2). The overexpression of Her-2eu can be determined using immunohistochemistry and/or fluorescence in situ hybridization. Patients with Her-2eu overexpressive breast cancer can be treated with the humanized antibody Trastuzumab. Some studies have reported hormone-receptor status discordance rates of 10-54% between primary and recurrent breast tumors (3-8). The mechanisms of change of hormone receptor and Her-2eu expression have not been explicitly identified. Possible explanations include tumor heterogeneity, genetic instability, or errors in the determination of the receptors.