Hormone Receptor-negative Metastatic Breast Cancer Presented as Cancer from an Unknown Primary Site

728 Copyrightc 2015 The Korean Association of Internal Medicine This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Received: 2014. 8. 14 Revised: 2014. 10. 2 Accepted: 2015. 7. 30