Yi et al. BMC Cancer 2010, 10:527 http://www.biomedcentral.com/1471-2407/10/527 R E S E A R C H A R T I C L E Open Access Favorable response to doxorubicin combination chemotherapy does not yield good clinical outcome in patients with metastatic breast cancer with triple-negative phenotype Seong Yoon Yi1, Jin Seok Ahn1*, Ji Eun Uhm1, Do Hyoung Lim1, Sang Hoon Ji1, Hyun Jung Jun1, Kyoung Ha Kim1, Myung Hee Chang1, Min Jae Park1, Eun Yoon Cho2, Yoon La Choi2, Yeon Hee Park1, Young-Hyuck Im1 Abstract Background: We analyzed the responses to first line treatment and clinical outcomes of metastatic breast cancer patients treated with palliative doxorubicin/cyclophosphamide (AC) according to molecular cancer subtype. Methods: A retrospective analysis was performed for 110 metastatic breast cancer patients selected on the basis of palliative AC treatment and the availability of immunohistochemical data for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER-2/neu) status. Results: Of the 110 patients analyzed, 71 (64.5%) were hormone receptor positive (HR+), 14 (12.7%) were HER2+, and 25 (22.7%) were triple negative (TN). There were no differences in age, stage at diagnosis, total number of cycles of palliative chemotherapy, incidence of visceral metastasis, and metastatic sites with the exception of liver among breast cancer subtypes. The overall response rates to AC were 55.9% for the HR+ subgroup, 42.9% for the HER2+ subgroup, and 56.5% for the TN subgroup. The progression-free survival (PFS) in patients with HER2+ and TN were significantly shorter than in the HR+ (median PFS, 9.1 vs 8.1 vs 11.5 months, respectively; p = 0.0002). The overall survival (OS) was 25.4 months in the TN subgroup and 27.3 months in HER2+ subgroup. The median OS for these two groups was significantly shorter than for patients in the HR+ subgroup (median, 38.5 months; 95% CI, 30.1-46.9 months; p < 0.0001). Conclusions: The response to palliative AC chemotherapy did not differ among breast cancer subtypes. Despite chemosensitivity for palliative AC, the TN subtype has a shorter overall survival than non-TN subtypes. Innovative treatment strategies should be developed to slow the course of disease. Background Breast cancer encompasses a heterogeneous group of diseases at the molecular level [1-4], and can be classi- fied into at least five distinct subtypes by gene expres- sion profiling: luminal A, luminal B, normal breast-like, ERBB2, and basal like [5-10]. Basal cell-like tumors typi- cally show low or no expression of HER2 and estrogen receptor (ER), and high expression of genes characteris- tic of basal epithelial cells [1,4,11-13]. These tumors * Correspondence: ajis@skku.edu 1Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon- dong Gangnam-gu, Seoul 135-710 Korea Full list of author information is available at the end of the article may share clinical and biologic properties with triple negative breast cancers (TNBCs) that lack expression of ER, progesterone receptor (PgR) and HER2 [5-8]. There is increasing evidence that breast cancer molecular sub- types differ in their responses to therapeutic agents. TNBC is considered a high-risk subtype because of its typically younger patient age, poorly differentiated tumor characteristics, and shortened survival of patients who often do not benefit from targeted therapies [11-19]. Because there is insufficient data on which to base treatment selection, no specific systemic treatment strategy is currently recommended for the treatment of TNBC. © 2010 Yi et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.