Comparison of the expression of prognostic biomarkers between primary tumor and axillary lymph node metastases in breast cancer

The prognosis and prediction of axillary lymph node (ALN) metastases in breast cancer is traditionally based upon the biomarkers status of the primary tumor. Some retrospective studies showed significant discordance in receptor expression between primary and metastatic tumors. We aim to prospectively assess the incidence of discordant biomarkers status in primary tumor and ALN metastases and to evaluate the role of ALN biopsies for the reassessment of receptor status. Tissue arrays were constructed from 54 breast cancer patients with ALN metastases diagnosed. Arrays were immuno-stained to compare protein expression of four biomarkers including estrogen receptor (ER), progesterone receptor (PR), HER2, and Ki67 by immunohistochemistry. The kappa value of consistency in the primary tumor and the metastatic lymph nodes were 0.465 for ER, 0.445 for PR, and 0.706 for HER2. Good consistency was shown for Ki67 expression in primary and metastases regions with T test. No significant difference is existed between primary tumor and ALN metastases. It is concluded that the good consistency is present for ER, PR, HER2 and Ki67 between the primary tumor and the metastatic lymph nodes, suggesting that ER, PR, HER2, or Ki67 status in primary tumors could reflect their status in ALN metastases.