Concordance between HER-2 and steroid hormone receptor expression between primary breast cancer, sentinel node metastases, and isolated tumor cells.

Our aim was to compare the HER-2 and hormone receptor status between primary tumor (PT) and sentinel node (SN) metastases in breast cancer. We analyzed 65 PTs with 42 macrometastases, 18 micrometastases, and 5 ITCs for the HER-2 amplification status and for the hormone receptor status. In HER-2-positive PTs, 26 of 29 metastases were HER-2-positive, including all six analyzed micrometastases and ITCs. Three macrometastases were HER-2-negative. In HER-2-negative PTs, 35 of 36 metastases were HER-2-negative. A low-grade HER-2 amplification was detected in one micrometastasis. A full concordance between the PT and SN metastases in both HER-2 amplification and ER and PR status was observed in 40 of 56 (71%) cases. These 40 fully concordant cases included 27 macrometastatic, 9 micrometastatic, and 4 ITC-cases. The concordance in HER-2, ER, and PR was high between the PT and their SN metastases. However, the concordance may be remarkably lower when analyzed simultaneously for all three predictive factors. Copyright 2010 Elsevier GmbH. All rights reserved.