Background: Single hormone receptor positive, especially single progesterone receptor positive (PgR+), although uncommon, is a unneglectable phenomenon given the large patient population. There is dispute as to single PgR positive is truly positive since PgR is a downstream molecule of estrogen receptor and when HER2 is negative at the same time, it is puzzling whether ER-/PgR+/HER2- breast cancer resemble triple negative breast cancer (TNBC) biologically and clinically. However, little is known about that. Therefore, we explore the role of single PgR positive by comparing ER-/PgR+/HER2- breast cancers with TNBCs. Methods: Among 3966 early breast cancer patients operated consecutively in Cancer Hospital, Chinese Academy of Medical Sciences from Jan 2005 to May 2008, 240 (6%) cases were identified as ER-/PgR+/Her2-and 348 (8.7%) cases as TNBCs. Clinicopathological characteristics and survival were analyzed respectively and then compared between 2 subtypes. Results: The average age of diagnosis was 49 yrs in both groups. For ER-/PgR+/HER2- patients, 213(88.8%) patients received adjuvant chemotherapy and 183 (76.3%) patients got adjuvant endocrine therapy. Axillary lymph node involvement was independent poor prognostic factor for Relapse-free survival (RFS) and overall survival (OS) (RFS: HR 1.728,P = 0.001; OS: HR 2.778, P<0.0001). Patients receiving adjuvant endocrine treatment had better survival than patients receiving no endocrine therapy (RFS: HR 0.594, P = 0.086; OS: HR 0.218,P<0.0001). Similarly, axillary lymph node involvement and large tumor size were found to be the poor prognostic factors for TNBC group. When compared with TNBCs, patients with ER-/PgR+/HER2- tumors tended to have lower tumor grade (P = 0.051) and smaller tumor size (P = 0.036). The metastatic patterns were comparable while RFS and OS demonstrated no difference between ER-/PgR+/HER2- and TNBC patients (5-year RFS rate: 80.7% vs 77.4%, P = 0.330; 5-year OS rate: 88.0% vs 85.2%, P = 0.290). Further analysis showed that ER-/PgR+/HER2- patients receiving adjuvant endocrine treatment had more favorable RFS and OS while ER-/PgR+/HER2- patients without endocrine therapy had worse overall survival compared with TNBC patients. Table 1: 5yr RFS and OS in ER-/PgR+/HER2- patients compared with TNBC patients  RFS  OS  5-year RFS rateHR(95%CI)P5-year OS rateHR(95%CI)PER-/PR+/HER2- with endocrine therapy (N = 183)84.0%0.686(0.453-1.038)0.07593.0%0.410(0.219-0.768)0.005ER-/PR+/HER2- without endocrine therapy (N = 57)70.1%1.392(0.824-2.353)0.21771.9%2.166(1.252-3.746)0.006TNBC as control(N = 348)77.4%  85.2%   Conclusions:This is the largest sample size to date looking at patients with ER-/PgR+/HER2- breast cancers specifically. It shows that without endocrine therapy, this group of patients may have worse outcomes than TNBC patients, indicating that it should be regarded as biologically and clinically distinct group of breast cancer and PgR intrinsically does not play a key role. PgR itself is not a good prognostic factor. However, adjuvant endocrine therapy could benefit this group of patients, suggesting estrogen signaling may still work via different pathways which might involve PgR. Further studies should be done to unravel the underlying mechanism. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-06-29.

Background: It is supposed that triple negative breast cancer (TNBC) may be more sensitive to DNA damage agents such as platinum. This study was designed to compare platinum-based regimen (docetaxel plus cisplatin) with non-platinum-based regimen (docetaxel plus capecitabine) in the first-line treatment of advanced triple negative breast cancer patients. Patients and Methods: This was a single-institution, randomized phase II clinical trial. Eligible TNBC women with first relapse or metastasis who had measurable disease were randomized (1:1) to receive either TP regimen (docetaxel 75mg/m2 plus cisplatin 75mg/m2 intravenous infusion day 1) or TX regimen (docetaxel 75mg/m2 intravenous infusion day 1 plus capecitabine 1000mg/m2 bid, two weeks on, one week off) every 3 weeks for up to 6 cycles, until disease progression, unacceptable toxicity or patient consent withdrawal. The primary endpoint was objective response rate (ORR) and secondary endpoints included progression free survival (PFS), overall survival (OS) and safety profile. To detect a difference of 0.35 in response rate between groups with a power of 80% and 2-sided significance level at 0.05, there should be at least 26 patients in each group. As of Jun 1st, 2011, 53 patients had been randomized and evaluated. Results: After a median follow-up of 24 months, the results showed much higher response rate in TP group than TX group although the clinical benefit rate was not significantly different. PFS was more than doubled in TP group compared with TX group. Overall survival was also statistically improved. G3/4 vomiting was merely observed in 3 patients from TP group. On the contrary, only patients in TX group (5/26) reported G2/3 Hand-Foot Syndrome. No differences were found in hematological and other non-hematological toxicities. Conclusions: Although it is a small sample size phase II study, it strongly suggested that cisplatin-contained TP regimen improved patient outcome, as measured by ORR, CBR, PFS and OS, compared with non-cisplatin-based TX regimen in the first-line treatment of advanced TNBC patients. This is the first prospective study to show superiority of cisplatin over capecitabine in TNBC. Together with additional ongoing clinical trials comparing platinum with other chemotherapeutic agents in various settings, the role of platinum in TNBC can be further elucidated. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-19-04.