Could the Breast Prognostic Biomarker Status Change During Disease Progression? An Immunohistochemical Comparison between Primary Tumors and Synchronous Nodal Metastasis

Background: Prognostic biomarkers in breast cancer are routinely investigated in the primary tumors to guidefurther management. However, it is proposed that the expression may change during the disease progression,and may result in a different immune profile in the metastatic nodes. This work aimed to investigate theexpression of breast prognostic biomarkers in primary tumors and in its axillary nodal metastasis, to estimatethe possible discordant expression. Materials and
Methods: 60 paired primary and axillary nodal metastasissamples were collected from patients with primary breast cancer with positive nodal deposits, diagnosed at theMaadi Military Hospital, Cairo, Egypt, during the year 2013. ER, PR and HER2 expression was assessed byimmunohistochemistry in all samples
Results: 48.3% of the included cases showed concordant results for bothER and PR receptors between the primary tumor and its nodal metastasis while 51.7% showed discordantresults and the discordance level was statistically significant. On the other hand, 70% of the cases showedconcordant Her2 results between the primary tumors and the nodal deposits, 30% showed discordant resultsand the difference was significant.
Conclusions: The study indicated that the discordance in ER and PR receptorexpression between the primary breast tumor and their nodal metastasis may be significant. The possible switchin the biomarker status during the disease progression is worth noting and may change the patient therapeuticplanning. So, whether the treatment selection should be based on biomarkers in the lymph node is a topic forfurther studies and future clinical trials.