Aims and background: To compare the expression of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER-2) in the primary site and the metastatic lesion of lymph nodes in invasive breast cancer for investigating whether the expression of these biomarkers in the primary site could act as a surrogate to the lymphatic metastatic lesion in the same patient.
Methods: In lymphatic metastatic lesion and corresponding primary lesion of 107 cases of invasive breast cancer, ER and PR statuses were assessed by immunohistochemistry (IHC). HER-2 expression level was evaluated by IHC and/or fluorescence in situ hybridization (FISH).
Results: In the primary lesions, 43.9% were ER positive; 46.7% were PR positive; 34.6% were HER-2 positive. In corresponding lymphatic metastatic lesions, the HER-2 status was concordant in 90 patients; 9 patients were diagnosed positive in metastatic lesion while negative in primary lesion; 8 patients were negative in metastatic lesion while positive in primary site (agreement, 84.1%; κ=0.647). A change in ER status was observed in 24 cases: 17 cases positive in metastatic site while negative in primary site; 7 cases negative in metastatic site while positive in primary site (agreement, 77.6%; κ=0.534). PR status discordance between the primary lesion and the metastatic regional lymph nodes was reported in 19 cases (agreement, 82.2%; κ=0.640).
Conclusions: This study revealed that there was only a moderate concordance of ER, PR and HER-2 status between primary tumors and metastatic lymph nodes. These results indicate that it was inappropriate to predict the status of ER, PR and HER-2 in metastatic lymph nodes based on the results of evaluation of that in primary lesions.
Keywords: Breast cancer; ER; HER-2; Metastatic lymph nodes; PR.
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