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Additional file 1: Supplementary data. Table S1 presenting patient characteristics. Table S2 presenting the distribution of clinical and immunohistochemical parameters according to PHD1 expression (0, >0). Table S3 presenting the distribution of clinical and immunohistochemical parameters according to PHD2 expression (0, 1, ≥2). Table S4 presenting the distribution of clinical and immunohistochemical parameters according to PHD3 expression (0, 1, ≥2). Table S5 presenting the distribution of clinical and immunohistochemical parameters according to PHD (all positive). Figure S1 showing a consort diagram. (DOC 169 KB)

Additional file of The prolyl hydroxylase enzymes are positively associated with hypoxia-inducible factor-1α and vascular endothelial growth factor in human breast cancer and alter in response to primary systemic treatment with epirubicin and tamoxifen

INTRODUCTION: Neoadjuvant hormonal therapy is generally considered a valid option for hormone receptor positive breast cancer (BC) patients who are unfit for chemotherapy or surgery. AIMS: Whilst numerous studies analyzed efficacy of neoadjuvant chemotherapy (CT) or endocrine therapy (HT) alone in hormone receptor positive patients, there is a lack of research looking at the usefulness of a preoperative combinatorial approach of CT and HT in this patient subgroup. METHODS: Using a predictive model previously described in the literature, developed to analyze the probability of benefit from preoperative chemotherapy, we were able to compare pathological complete response (pCR) rates expected with the use of CT alone with the pCR rates reported in a population of 192 patients treated with the combination of tamoxifen plus anthracycline-based CT at Cremona Hospital between 2003 and 2006. RESULTS: Even with a relatively small patient population, this approach provided insightful information for the selection of hormone receptor positive BC patients most likely to benefit from the use of preoperative HT and CT in combination. Whilst no statistically significant benefit was obtained with the addition of tamoxifen to neoadjuvant chemotherapy in the entire population, or in any of the molecular stratification subgroups, the analysis of the calibration curve showed that a combinatorial approach may improve pCR in patients with luminal B tumors. More specific trials should be designed to confirm our initial results. CONCLUSION: To the best of our knowledge, this is the first report investigating the efficacy of the combination of CT and HT in the neoadjuvant treatment of hormone receptor positive BC.

Introduction: The purpose of the present study was to investigate the relationship of expression of hypoxia inducible factor (HIF)-1α-modifying enzymes prolyl hydroxylase (PHD)1, PHD2 and PHD3 to response of tumours and survival in breast cancer patients enrolled in a phase II trial of neoadjuvant anthracycline and tamoxifen therapy.Methods: The expression of PHD1, PHD2 and PHD3 together with HIF-1α and the HIF-inducible genes vascular endothelial cell growth factor (VEGF) and carbonic anhydrase IX were assessed by immunohistochemistry using a tissue microarray approach in 211 patients with T2-4 N0-1 breast cancer enrolled in a randomised trial comparing single-agent epirubicin versus epirubicin and tamoxifen as the primary systemic treatment.Results: PHD1, PHD2 and PHD3 were detected in 47/179 (26.7%), 85/163 (52.2%) and 69/177 (39%) of tumours at baseline. PHD2 and PHD3 expression was moderate/strong whereas PHD1 expression was generally weak. There was a significant positive correlation between HIF-1α and PHD1 (P = 0.002) and PHD3 (P < 0.05) but not PHD2 (P = 0.41). There was a significant positive relationship between VEGF and PHD1 (P < 0.008) and PHD3 (P = 0.001) but not PHD2 (P = 0.09). PHD1, PHD2 and PHD3 expression was significantly increased after epirubicin therapy (all P < 0.000) with no significant difference in PHD changes between the treatment arms. There was no significant difference in response in tumours that expressed PHDs and PHD expression was not associated with survival.Conclusions: Although expression of the PHDs was not related to response or survival in patients receiving neoadjuvant epirubicin, our data provide the first evidence that these enzymes are upregulated on therapy in breast cancer and that the biological effects independent of HIF make them therapeutic targets. © 2011 Fox et al.; licensee BioMed Central Ltd.

PurposeWe aimed to identify signaling pathways involved in the response and resistance to aromatase inhibitor therapy in patients with breast cancer.Patients and MethodsOne hundred fourteen women with T2-4 N0-1, estrogen receptor (ER) α–positive tumors were randomly assigned to neoadjuvant letrozole or letrozole plus metronomic cyclophosphamide. Twenty-four tumor proteins involved in apoptosis, cell survival, hypoxia, angiogenesis, growth factor, and hormone signaling were assessed by immunohistochemistry in pretreatment samples (eg, caspase 3, phospho- mammalian target of rapamycin, hypoxia-inducible factor 1α [HIF-1α], vascular endothelial growth factor, mitogen-activated protein kinase [MAPK], phosphorylated epidermal growth factor receptor, phosphorylated ERα [pERα]). A multivariate generalized linear regression approach was applied using a penalized least-square minimization to perform variable selection and regularization. Ten-fold cross-validation and iterative leave-one-out were employed to validate and test the model, respectively. Tumor size, nodal status, age, tumor grade, histological type, and treatment were included in the analysis.ResultsNinety-one patients (81%) attained a disease response, 48 achieved a complete clinical response (43%) whereas 22 did not respond (19%). Increased pERα and decreased p44/42 MAPK were significant factors for complete response to treatment in all leave-one-out iterations. Increased p44/42 MAPK and HIF-1α were significant factors for treatment resistance in all leave-one-out iterations. There was no significant interaction between these variables and treatment.ConclusionActivated ERα form was an independent factor for sensitivity to chemoendocrine treatment, whereas HIF-1α and p44/42 MAPK were independent factors for resistance. Although further confirmatory analyses are needed, these findings have clear potential implications for future strategies in the management of clinical trials with aromatase inhibitors in the breast cancer.

The OLTRE trial (ClinicalTrials.gov number: NCT02681562) is an open-label, ‘window of opportunity’ Phase II controlled trial to evaluate the biological activity of olaparib in locally advanced triple-negative breast cancer compared with other subtypes of locally advanced breast cancer patients carrying germinal BRCA mutation receiving olaparib with the same treatment approach. The primary end point is to investigate the correlation between baseline gene and protein expression profile in order to identify possible predictive markers of response to olaparib. The OLTRE trial is expected to identify the surrogate markers of the biological activity of olaparib in the treatment of patients with triple-negative breast cancer.

Purpose: We have shown previously that tumor infiltration by FOXP3+ regulatory T cells (Treg) is associated with increased relapse and shorter survival of patients with both in situ and invasive breast cancer. Because estrogen regulates Treg numbers in mice and promotes the proliferation of human Tregs, we hypothesized that blocking estrogen receptor-α signaling would abrogate Tregs and be associated with response to hormonal therapy and increased survival. Experimental Design: FOXP3+ Tregs were quantified in tumor samples collected at baseline by incisional biopsy and after 6 months at definitive surgery in 83 elderly breast cancer patients (T2-4 N0-1) enrolled in a randomized phase II trial based on 6 months of primary letrozole (2.5 mg/d) or 6 months of letrozole plus oral “metronomic” cyclophosphamide (50 mg/d). Results: Treg number ranged from 0 to 380 (median, 30) before treatment and from 0 to 300 (median, 8) after treatment. There was a significant reduction in Tregs in letrozole and letrozole-cyclophosphamide patients (P < 0.0001 and P < 0.002, respectively) after treatment. Treg number at residual histology was inversely related with response (P < 0.03 and P = 0.50, respectively) and a greater Treg reduction was observed in responding patients (P < 0.03). Conclusion: This study suggests that aromatase inhibitors may have an indirect antitumor mechanism of action through reducing Tregs in breast tumors and may be of use in estrogen receptor-α-negative tumors in combination with immunotherapy approaches.

// Manuela Milani 1, * , Sergio Venturini 2, * , Simone Bonardi 1 , Giovanni Allevi 1 , Carla Strina 1 , Maria Rosa Cappelletti 1 , Silvia Paola Corona 3 , Sergio Aguggini 1 , Alberto Bottini 1 , Alfredo Berruti 4 , Adrian Jubb 5 , Leticia Campo 5 , Adrian L. Harris 5 , Kevin Gatter 5 , Stephen B. Fox 6 , Daniele Generali 1, 7 and Giandomenico Roviello 7, 8 1 U.O. Multidisciplinare di Patologia Mammaria, U.S Terapia Molecolare e Farmacogenomica, ASST Cremona, Viale Concordia 1, Cremona, Italy 2 CE.R.G.A.S., Universita Bocconi, Milano, Italy 3 Peter MacCallum Cancer Centre, Bentleigh East VIC, Australia 4 U.O. Oncologia Medica, Spedali Civili si Brescia, University of Brescia, Brescia, Italy 5 Molecular Oncology Laboratories, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS, UK 6 Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, Victoria, Australia 7 Department of Medical, Surgery and Health Sciences, University of Trieste, Piazza Ospitale 1, Trieste, Italy 8 Department of Oncology, Medical Oncology Unit, San Donato Hospital, Italy * Manuela Milani and Sergio Venturini contributed equally to the study Correspondence to: Daniele Generali, email: daniele.generali@gmail.com Keywords: epirubicin resistance, haemoglobin, hypoxia-inducible factor, neoadjuvant, breast cancer Received: September 21, 2015 Accepted: July 18, 2017 Published: August 14, 2017 ABSTRACT Purpose: To identify hypoxia-related biomarkers indicative of response and resistance to epirubicin treatment in patients with locally advanced breast cancer. Patients and Methods: One hundred seventy-six women with T2-4 N0-1 breast tumours were randomly assigned to receive epirubicin 120 mg/m2/1-21 (EPI ARM), epirubicin 120 mg/m2/1-21 + erythropoietin 10.000 IU sc three times weekly (EPI-EPO ARM) and epirubicin 40 mg/m2/w-q21 (EPI-W ARM). Sixteen tumour proteins involved in cell survival, hypoxia, angiogenesis and growth factor, were assessed by immunohistochemistry in pre-treatment samples. A multivariate generalized linear regression approach was applied using a penalized least-square minimization to perform variable selection and regularization. Results: VEGF and GLUT-1 expression were significantly positively associated with complete response (CR) to treatment in all leave-one-out iterations. Bcl-2 expression was inversely correlated with pCR, whilst EPO expression was positively correlated with pathological complete response (pCR). Haemaglobin and HIF-1a nuclear expression were inversely correlated with pCR. HB and HIF-1a expression were associated with a higher risk of relapse and overall survival. Conclusion: Hypoxic biomarkers determines the epirubicin resistance in breast cancer. Assessment of such biomarkers, may be useful for predicting chemosensitivity and also anthracycline-based treatment outcome.

INTRODUCTION: Recently the combination of the mammalian target of rapamycin (mTOR) inhibitor everolimus and the aromatase inhibitor exemestane has been shown to double the progression-free survival rate in advanced breast cancer. However, the effect of the interrelated pathways of hypoxia-inducible factor-1α (HIF-1α) and mTOR signaling, both of which are associated with a more aggressive breast cancer phenotype and endocrine resistance, on response in the neoadjuvant setting is unknown. We, therefore, have investigated the influence of these pathways with the aim of better defining those patients most likely to benefit from an endocrine-based therapy associated with/without mTOR inhibitors. PATIENTS AND METHODS: A total of 107 women with T2-4 N0-1 and estrogen receptor-positive breast cancer were randomly assigned to 6 months of primary letrozole (2.5 mg/daily) (LET) or LET plus oral "metronomic" cyclophosphamide (50mg/daily) (LET-CYC). Phospo-mTOR and HIF-1α were evaluated in tumor specimens collected before and after treatment using a tissue microarray format. RESULTS: LET-based therapy induced a downregulation of phospho-mTOR and HIF-1α expression (P = .0001 and P < .004, respectively). The reduction of HIF-1α expression observed was positively correlated with phospho-mTOR reduction (P < .03); however, no treatment interaction between the two proteins was detected. HIF-1α expression was significantly modulated by the treatment (P < .004) with a reduction both in the LET arm (45%, n = 36/80) (P = .05) and LET-CYC arm (55%, n = 44/80) (P = .04). HIF-1α reduction showed a relationship with clinical response confined in LET arm only (P < .03). CONCLUSIONS: In this neoadjuvant population, LET was able to modulate the phospho-mTOR and HIF-1α pathways and may define a subpopulation of nonresponders who may be most likely to benefit from mTOR inhibitors

The purpose of this study is to investigate the role of carbonic anhydrase IX (CAIX) expression in predicting the response to epirubicin and disease-free survival (DFS) in breast cancer patients enrolled in a single institution trial of primary anthracycline and tamoxifen therapy. CAIX expression was assessed in 183 patients with T2–4 N0–1 breast cancer enrolled in a randomized trial comparing four cycles of single agent epirubicin versus epirubicin + tamoxifen as primary systemic treatment. All patients received postoperatively four cycles of the four weekly i.v. cyclophosphamide, methotrexate, 5-fluorouracil regimen. Patients with estrogen receptor (ER)-positive primary tumors received 5 years of adjuvant tamoxifen. Pretreatment, p53 (P = 0.007), c-erbB2 (P < 0.01), and Ki67 (P = 0.02) were directly associated with CAIX expression, while bcl2 (P < 0.000) and ER (P = 0.000) and progesterone receptor (PgR; P < 0.01) were inversely correlated. In multivariate analysis, only high p53 and low bcl2 were independently associated with CAIX positivity. CAIX immunostaining was significantly associated with poor outcome for DFS (P < 0.002) and overall survival (P = 0.001). In multivariate analysis, a significant interaction was found between CAIX and markers of hormone sensitivity, bcl2 (P = 0.01), ER (P = 0.02), PgR (P = 0.02), and lymph node involvement (P = 0.04), in predicting DFS. Presently, there are few clinical markers of resistance to tamoxifen treatment in ER-positive tumors. CAIX expression in breast cancer patients shows a negative predictive role of treatment efficacy in ER-positive patients on the adjuvant tamoxifen after primary chemo-endocrine therapy. Studies investigating the effects of pH on tamoxifen uptake and the effects of therapy with CA inhibitors are planned.

Summary Purpose. To investigate whether magnetic resonance imaging (MRI) is superior to clinical palpation in the assessment of response of breast cancer to primary chemotherapy (PC). Patients and methods. Seventy-three patients with T2–4, N0, M0 breast cancer were treated with 3–4 cycles of single agent epirubicin before definitive surgery. MRI was performed at baseline condition and at the end of chemotherapy. Results. According to the WHO criteria, 20 (27.4%) patients attained a complete response (CR) by clinical palpation and 41 (56.2%) a partial response. The corresponding response rate by MRI was 11 (15.1%) and 34 (46.6%), respectively. Residual tumor assessed by MRI better correlated with pathologic measurements (Spearman r: 0.72) than residual tumor assessed by clinical palpation (Spearman r: 0.58). Post-chemotherapy histology evaluation revealed pathologic CR in three cases, only one of them was considered as complete responder by MRI. Residual disease consisted in in situ carcinoma in four cases, one of them was complete responder at MRI, the remaining three showed residual abnormal contrast enhancement indistinguishable from that of invasive tumors. Conclusions. As compared to pathology specimens, MRI is able to represent the extent of cancer more accurately than clinical palpation. It constitutes a promising technique in assessing the BC response to PC. The current limit of MRI is the scarce specificity in predicting the nature of residual disease.

Vascular endothelial growth factor A (VEGF-A) and vascular endothelial growth factor receptor 2 (VEGFR2) are the key factors mediating neo-vascularization. They are often coexpressed in breast cancer. Sex steroids may stimulate angiogenesis via the estrogen receptor (ER) pathway. We investigated to compare the effects of the addition of tamoxifen to epirubicin versus epirubicin alone on VEGF and VEGFR2 expression in breast cancer patients. The expression of VEGF and VEGFR2 was assessed on tissue microarray by immunohistochemistry at baseline conditions and after treatments in the case of 191 patients with T2-4 N0-1 breast cancer enrolled in a randomized trial comparing four cycles of single agent epirubicin versus epirubicin plus tamoxifen as primary systemic treatment. Epirubicin alone failed to induce changes in VEGF expression (P = 0.54), while the addition of tamoxifen to epirubicin resulted in a significant reduction in VEGF expression (P < 0.001). As a consequence, baseline VEGF had a negative prognostic role in patients who received epirubicin alone but not in patients receiving epirubicin plus tamoxifen (interaction test P < 0.05). VEGFR2 expression increased at residual tumor histology in both treatment arms, with a lesser extent in patients receiving tamoxifen plus epirubicin. Decrease in VEGFR2 expression was significantly associated with response rate (P = 0.02). The addition of tamoxifen to epirubicin resulted in a suppression of a key angiogenic pathway. These data suggest a potential synergism of these two drugs.

Purpose: The phosphatidylinositol 3′-kinase (PI3K)/AKT/molecular target of rapamycin (mTOR) pathway is involved in the development of tumor resistance to endocrine therapy in breast cancer cell lines and represents an attractive target for pharmacologic intervention. However, the effects of endocrine therapy with aromatase inhibitors on in vivo expression of this signaling cascade, and its relation to tumor response and patient outcome, is unknown. Experimental Design: PI3K, phospho-AKT (pAKT) and phospho-mTOR were assessed by immunohistochemistry on tumor specimens collected at baseline and after 6 months of treatment in 113 elderly breast cancer patients consecutively enrolled in a randomized phase II trial of primary letrozole therapy and letrozole associated with metronomic cyclophosphamide. Results: Basal expression of the pathway was not significantly correlated with response or patient outcome. Both letrozole alone and letrozole with cyclophosphamide resulted in a significant reduction of PI3K expression (P = 0.02 and P < 0.005, respectively) and phospho-mTOR expression (P = 0.0001 and P = 0.0001, respectively). pAKT showed no change in the letrozole arm, whereas it was significantly decreased in the letrozole plus cyclophosphamide arm (P < 0.005). pAKT expression reduction was associated with a greater response rate (P = 0.05) and greater reduction in Ki67 expression (P = 0.05). Phospho-mTOR expression reduction was associated with a significantly longer disease-free survival in a multivariate analysis (P = 0.02). Conclusions: Letrozole inhibits key molecules in the PI3K pathway that are important targets of new drugs being developed to overcome resistance. Changes in these molecules may have prognostic significance. These results should be taken into account when planning prospective trials testing up-front aromatase inhibitor with drugs targeting the PI3K/AKT/mTOR signaling pathway.

Purpose: To examine the in vitro regulation of hepatocyte growth factor activator inhibitor type 2 (HAI-2) in breast cancer cells and the in vivo predictive role for the efficacy of chemoendocrine primary therapy in patients with breast cancer. Materials and Methods: HAI-2 regulation was studied in a panel of breast cancer cell lines comparing normoxia to hypoxia. The effect of HIF-1α RNAi on HAI-2 expression was evaluated in these cells. HAI-2 was examined in breast cancer using in situ hybridization and immunohistochemistry. The HAI-2 predictive role was assessed in T2-4 N0-1 breast cancers (n = 177) enrolled in a neoadjuvant randomized trial comparing epirubicin versus epirubicin + tamoxifen. Results: HAI-2 mRNA and protein were regulated by hypoxia in the c-erbB2–positive cell lines, SKBR3 and BT474, and controlled by HIF-1α in these cells. Immunohistochemistry confirmed this profile with high expression of HAI-2 in c-erbB2–positive breast cancer. HAI-2 was correlated with T status (P < 0.004), node involvement (P = 0.01), and c-erbB2 expression (P = 0.05). HAI-2 also correlated with hypoxia markers such as carbonic anhydrase IX expression (P = 0.01) and HIF-1α. Additionally, high levels of HAI-2 were a significant predictor for poor clinical complete response to preoperative epirubicin in univariate (P = 0.01) and multivariate analyses (P = 0.016). No correlation with disease-free survival and survival was observed. Conclusion: HAI-2 expression in breast cancer correlated with tumor aggressiveness in vivo. It is a HIF target in c-erbB2–positive cells and it is an independent negative predictive factor of efficacy of anthracycline therapy. The interaction of HAI-2 with the hepatocyte growth factor activation pathway may be a useful site for therapeutic intervention.

BACKGROUND: Bone metastases are devastating events resulting in disruption of local bone remodeling processes. Physiological bone turnover has a circadian rhythm. No data are available on the circadian pattern of bone turnover markers in patients with bone metastases. METHODS: Twenty post-menopausal women with breast cancer (BC) at first disease relapse and at least one bone metastasis were consecutively recruited. Twenty healthy women served as controls. Patients were free from concomitant chemotherapy/endocrine therapy. Throughout a 24-h period, urine samples were collected at 4-h intervals, and blood samples were collected at 4-h intervals between 08:00 and 24:00, and at 2-h intervals between 24:00 and 08:00. Serum osteocalcin (OC), total and bone-alkaline phosphatase (tALP and bALP, respectively) and C-terminal telopeptide of type I collagen (CTX), and urinary NTX and free deoxypyridinoline (fDPD) were measured together with serum parathyroid hormone (PTH) and serum and urinary calcium and phosphorus. Temporal variations of measured analytes were assessed by ANOVA and the COSINOR model. RESULTS: At 08:00, patients had higher levels of bone resorption indices (NTX, CTX and fDPD) than controls (p

Purpose To investigate the activity of letrozole plus/minus oral metronomic cyclophophamide as primary systemic treatment (PST) in elderly breast cancer patients. Methods One hundred fourteen consecutive elderly women with T2-4 N0-1 and estrogen receptor–positive breast cancer were randomly assigned to primary letrozole therapy (2.5 mg daily for 6 months) or a combination of letrozole plus oral cyclophosphamide (50 mg/daily for 6 months) in an open-labeled, randomized phase II trial. Tumor response was assessed clinically, and tumor Ki67 index and vascular endothelial growth factor (VEGF) -A levels were measured before and after treatment. Results Overall response rate was 71.9% (95% CI, 60.0 to 83.8) in the 57 patients randomly assigned to receive primary letrozole and 87.7% (95% CI, 78.6 to 96.2) in the 57 patients randomly assigned to receive letrozole plus cyclophosphamide. The difference in activity between treatment arms was predominantly confined to patients with ductal histology. There was a significantly greater suppression of Ki67 and VEGF-A expression in the letrozole/cyclophosphamide-treated group than in the letrozole-treated group, leading to lower Ki67 and VEGF expression at post-treatment residual histology (P = .03 and P = .002, respectively). Conclusion Both letrozole and letrozole plus cyclophosphamide treatments appeared active as PST in elderly breast cancer patients. Metronomic scheduling of cyclophosphamide may have an antiangiogenetic effect and the combination of letrozole plus cyclophosphamide warrants testing in a randomized phase III trial.

Purpose: To investigate the relationship of hypoxia-inducible factor-1α (HIF-1α) tumor expression in predicting the response to epirubicin and disease-free survival (DFS) in patients with breast cancer enrolled in a single institution trial of primary anthracycline and tamoxifen therapy. Experimental Design: The expression of HIF-1α was assessed by immunohistochemistry in 187 patients with T2-4 N0-1 breast cancer enrolled in a randomized trial comparing four cycles of single agent epirubicin versus epirubicin + tamoxifen as primary systemic treatment. All patients postoperatively received four cycles of the four weekly i.v. CMF regimen (cyclophosphamide, methotrexate, and 5-fluorouracil). Patients with estrogen receptor (ER)-positive primary tumors also underwent 5 years of treatment with adjuvant tamoxifen. Carbonic anhydrase IX (CAIX) was also scored as a marker of HIF activity. Results: Overall response to therapy progressively decreased with increasing tumor HIF-1α (P < 0.05), and HIF-1α was an independent predictor of response (P < 0.048). HIF-1α expression was also associated with a significantly shorter DFS (P < 0.02) in all patients and in ER-positive but not in ER-negative patients. Furthermore, CAIX positivity conferred a significantly shorter DFS (P = 0.02) compared with CAIX-negative tumors in patients with HIF-1α-negative tumors. Conclusions: HIF-1α expression in patients with breast cancer is a marker of poor therapy response and outcome, especially in ER-positive patients. The combination of two hypoxia markers has greater utility than assessing just one, and patients with hypoxia markers in their tumors may be suitable for administration of drugs that reduce HIF-1α expression and increase oxygen delivery to the tumor bed before starting neoadjuvant therapies.

Aim: Treatment of triple-negative breast cancer (TNBC) imposes great challenges, due to a lack of molecular targets. While use of gonadotropin-releasing hormone (GnRH) analogs has been validated in ER-positive breast cancer, this option has not been investigated in TNBC, even though a significant portion of these tumors upregulate GnRH receptors. We performed a meta-analysis of the literature to evaluate the effect of GnRH analogs in TNBC. Methods: Four studies were included in this study. Results: We detected a non-significant improvement in overall survival with GnRH analogs, while progression-free survival was unchanged. Discussion: The majority of the trials evaluated in this analysis were designed to test efficacy of GnRH analogs in preventing premature ovarian failure. This may represent a limitation of our study as these trials were not specifically designed to detect differences in survival outcome measures. Conclusion: Our results suggest that GnRH analogs may be useful as a targeted therapy in TNBC. Randomized prospective clinical trials are needed to investigate this hypothesis in the clinic.