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INTRODUCTION: Estrogen receptors (ER), progesterone receptors (PR), and epidermal growth factor (HER2) are prognostic and predictive factors for breast carcinoma. We determined them by immunohistochemistry (IHC) on cell blocks from fine-needle aspirates (FNA) of metastatic breast carcinoma to axillary lymphnodes and compared them with that reported in the primary breast carcinoma (PBC) to document any change in their expression for future management. MATERIALS AND METHODS: ER, PR, and HER2 by IHC and HER2 oncogene by fluorescent in-situ hybridization (FISH) were studied on cell blocks of FNA of axillary lymphnodes in 53 of 94 PBC cases from 2012 to 2016. RESULTS: In 25 of 38 (65.8%) ER, PR negative PBC the metastasis on FNA was ER, PR+, whereas the 15 (28.3%) ER, PRPBC remained negative. In 10 of 11 (91%) of HER2-IHC+, PBC the metastatic tumor was HER2-IHC+. 7 of 32 (21.9%) HER2-IHC negative PBC were HER2-IHC+ in metastatic tumor. HER2-FISH was performed in 37 cases on FNA. Six of 37 were HER2 amplified/positive, whereas 9 and 19 remained equivocal and negative for HER2 copy number, and 3 were not interpretable. All the 6 HER2-FISH+ cases were positive by IHC. In our study, 34.2% of ER, PR+ cases of PBC became ER, PR- in the metastatic tumor and 21.9% of HER2-IHC negative PBC became HER2-IHC+ in the metastatic aspirate. CONCLUSION: ER, PR, and HER2 by IHC in cell blocks of metastatic lymphnodes are reliable. Change in receptor (34.2%) and HER2 status (21.9%) was documented, which is of clinical significance as these patients warrant a change of management.
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BACKGROUND: Documenting the four molecular subtypes of breast carcinoma is significant as they determine response to therapy, disease free interval and survival. Our aim was to document the subtypes defined by immunohistochemistry (IHC) expression of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2): namely ER + PR+ HER2+; ER + PR + HER2-; ER-PR-HER2+; and ER-PR-HER2- in metastatic breast carcinoma in pleural fluid and compare them with their expression in the primary breast tumor. METHODS: Over a period of 18 months, 13 cases of invasive breast carcinoma with metastases to the pleural cavity were studied for subtypes. ER, PR, and HER2 were determined by IHC in the primary breast tumor and the cell blocks of the pleural fluid with metastatic carcinoma. RESULTS: Age ranged from 33 to 75 years. The primary tumor was ER + PR + HER2+; ER + PR + HER2-; ER-PR-HER2+ and ER-PR-HER2- in 2,9,0 and two cases, respectively while the metastatic tumor in pleural fluid was ER + PR + HER2+; ER + PR + HER2-; ER-PR- HER2+ and ER-PR-HER2- in 6, 3, 3, and 1, respectively. In five cases there was complete correlation between the primary and metastatic tumor. In 7 cases with HER2- primary tumor the metastases was HER2+. One from ER + PR+ HER2- primary tumor showed triple negative expression in the metastasis. CONCLUSIONS: Determining the molecular subtype in metastatic breast carcinoma is of importance as it affects the management. In our series 63% of metastatic tumors to the pleural fluid became HER2 positive and would thus require appropriate therapy. Diagn. Cytopathol. 2016;44:980-986. © 2016 Wiley Periodicals, Inc.
