三阴性乳腺癌的系统治疗策略

三阴性乳腺癌被定义为雌激素受体（ER）、孕激素受体（PR）和人表皮生长因子受体2（EGFR2）均阴性的乳腺癌,它具有独特的生物学特性及临床特征。大多数三阴性乳腺癌有基底细胞样表型的特点以及相同的临床病理特征,并且与遗传性基因BRCA1相关。三阴性乳腺癌患者不同的亚群对于特定的靶向治疗有着不同的疗效。我们评估了三阴性乳腺癌化疗联合靶向治疗的方案,系统评价了PubMed数据库上对接受了化疗和靶向治疗的乳腺癌女性患者的随机临床试验报告。三阴性乳腺癌是一个对化疗敏感的实体肿瘤,单纯结合靶向药物并不能使疗效显著的提高,合理地选择病人,理性地结合靶向药物,才能使疗效更好。     

Targeting triple-negative breast cancer: optimising therapeutic outcomes

Background Triple-negative breast cancer (TNBC) is a distinct subset of breast cancer (BC) defined by the lack of immunohistochemical expression of the estrogen and progesterone receptors and human epidermal growth factor receptor 2. It is highly heterogeneous and displays overlapping characteristics with both basal-like and BC susceptibility gene 1 and 2 mutant BCs. This review evaluates the activity of emerging targeted agents in TNBC. Design A systematic review of PubMed and conference databases was carried out to identify randomised clinical trials reporting outcomes in women with TNBC treated with targeted and platinum-based therapies. Results and Discussion Our review identified TNBC studies of agents with different mechanisms of action, including induction of synthetic lethality and inhibition of angiogenesis, growth, and survival pathways. Combining targeted agents with chemotherapy in TNBC produced only modest gains in progression-free survival, and had little impact on survival. Six TNBC subgroups have been identified and found to differentially respond to specific targeted agents. The use of biological preselection to guide therapy will improve therapeutic indices in target-bearing populations. Conclusion Ongoing clinical trials of targeted agents in unselected TNBC populations have yet to produce substantial improvements in outcomes, and advancements will depend on their development in target-selected populations.     

三阴性乳腺癌的靶向治疗研究进展

 三阴性乳腺癌（TNBC）是乳腺癌的一种特殊亚型,对内分泌治疗无效,针对Her-2靶点的靶向治疗如赫赛汀、拉帕替尼等也并不适用。目前,常规化疗是内科治疗TNBC的惟一途径。寻找TNBC的治疗靶点是目前乳腺癌的研究热点之一,正在研发的新靶向治疗药物包括PARP-1抑制剂、EGFR抑制剂、CXCR4抑制剂、抗血管生成、Src酪氨酸激酶抑制剂、mTOR抑制剂等。     

Dissecting the heterogeneity of triple-negative breast cancer

Triple-negative breast cancer (TNBC) accounts for 15% to 20% of breast cancers. It is a heterogeneous disease, not only on the molecular level, but also on the pathologic and clinical levels. TNBC is associated with a significantly higher probability of relapse and poorer overall survival in the first few years after diagnosis when compared with other breast cancer subtypes. This is observed despite its usual high sensitivity to chemotherapy. In the advanced setting, responses observed with chemotherapy lack durability. Early-stage clinical studies suggested impressive potential when a poly (ADP-ribose) polymerase (PARP) inhibitor is given for the treatment of advanced TNBC with BRCA gene dysfunction. The molecular complexity of TNBC has led to proposed subclassifications, which will be of great value for the development of targeted therapies. In this review, we discuss the biology of TNBC at the pathologic and the molecular levels. We also elaborate on the role of systemic therapies and the results of the first phase III clinical trial evaluating the addition of iniparib, a novel investigational anticancer agent that does not possess characteristics typical of the PARP inhibitor class, in combination with chemotherapy in advanced TNBC.     

Metastatic triple negative breast cancer: Optimizing treatment options,new and emerging targeted therapies

Triple negative breast cancer (TNBC) is a heterogeneous disease, not only on the molecular level, but also on the pathologic and clinical levels. It also has a distinct epidemiology. TNBCs are frequently of high histologic grade, typically more aggressive and difficult to treat than hormone receptor‐positive tumors, and they are associated with a higher risk of early relapse with visceral metastasis after surgery, chemotherapy and/or radiotherapy. The lack of estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2 expression precludes the use of targeted therapies in advanced stages, and the only approved systemic treatment option is chemotherapy with or without bevacizumab. In patients with advanced TNBC, responses to chemotherapy occur, but are often of short duration and it is associated with poor prognosis. The median overall survival for patients with metastatic TNBC is about 9–12 months with conventional cytotoxic agents. Given the suboptimal outcomes with chemotherapy, new targeted therapies for TNBC are urgently needed. This review summarizes the clinical efficacy, perspectives and future challenges of using new treatment options for metastatic TNBC, such as poly‐ADP‐ribose‐polymerase inhibitors, antiandrogen therapies and immune checkpoint inhibitors (antiprogrammed death receptor‐1/PD‐L1 monoclonal antibodies).     

Targeting the PI3-kinase pathway in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is characterised by poor outcomes and a historical lack of targeted therapies. Dysregulation of signalling through the phosphoinositide 3 (PI3)-kinase and AKT signalling pathway is one of the most frequent oncogenic aberrations of TNBC. Although mutations in individual genes occur relatively rarely, combined activating mutations in PIK3CA and AKT1, with inactivating mutations in phosphatase and tensin homologue, occur in ∼25%‒30% of advanced TNBC. Recent randomised trials suggest improved progression-free survival (PFS) with AKT-inhibitors in combination with first-line chemotherapy for patients with TNBC and pathway genetic aberrations. We review the evidence for PI3K pathway activation in TNBC, and clinical trial data for PI3K, AKT and mammalian target of rapamycin inhibitors in TNBC. We discuss uncertainty over defining which cancers have pathway activation and the future overlap between immunotherapy and pathway targeting.     

Triple negative breast cancer: unmet medical needs

Triple negative breast cancer (TNBC) is an aggressive clinical phenotype characterized by lack of expression (or minimal expression) of estrogen receptor (ER) and progesterone receptor (PR) as well as an absence of human epidermal growth factor receptor-2 (HER2) overexpression. It shows substantial overlap with basal-type and BRCA1-related breast cancers, both of which also have aggressive clinical courses. However, this overlap is not complete, and the expression of ER, PR, and HER2 has been noted in basal-like tumors. TNBC also includes the normal-like subtype, and not all patients with TNBC harbor BRCA1 mutations. Because of its expression profile, TNBC is not amenable to treatment with hormone therapy or the anti-HER2 monoclonal antibody trastuzumab, and systemic treatment options are currently limited to cytotoxic chemotherapy. Overall survival, whether in early-stage or advanced disease, is poor compared with that in patients who have other phenotypes. A number of targeted approaches to TNBC are undergoing clinical evaluation, including the use of agents with poly(ADP-ribose) polymerase inhibitory properties such as iniparib (the United States Adopted Name for the investigational agent BSI-201), olaparib (AZD2281), and veliparib (ABT-888), antiangiogenic agents such as bevacizumab and sunitinib, and epidermal growth factor receptor blockers such as cetuximab and erlotinib. Encouraging results with some of these agents have been reported, thereby offering the promise for improved outcomes in patients with TNBC. The clinical characteristics of TNBC and clinical experience to date with novel targeted agents under development for this aggressive phenotype is reviewed.     

Clinicopathological features and treatment strategy for triple-negative breast cancer

Breast cancers are divided into at least 4 subtypes on the basis of gene expression profiles and expression of receptors (hormone receptors (HR) and HER2) as measured by immunohistochemistry. These subtypes have different prognoses and responses to treatments such as endocrine manipulation, anti-HER2 therapy, and chemotherapy. Triple-negative breast cancer (TNBC) is immunohistochemically defined as lacking estrogen and progesterone receptors and not overexpressing HER2. TNBC accounts for approximately 15% of breast cancer patients, and is more chemosensitive but has a worse prognosis than the HR-positive/HER2-negative phenotype. TNBC is a heterogeneous disease that does not offer specific targets in the same way as HR-positive and HER2-positive breast cancers, and is similar to basal-like breast cancer and BRCA1-related breast cancer. At present, the lack of highly effective therapeutic targets for TNBC leaves standard chemotherapy, for example the combination of anthracycline and taxane, as the only medical treatment, but this is insufficiently efficacious. Novel approaches for TNBC, for example DNA damaging agents, PARP-1 inhibitors, receptor tyrosin kinase inhibitors (TKIs), and antiangiogenesis agents, have been examined in clinical settings. Concerning therapeutic strategies for TNBC, it is most important to develop novel effective approaches for TNBC treatment and high-throughput predictive tools for standard chemotherapy and novel agents.     

Epidermal growth factor receptor as a potential therapeutic target in triple-negative breast cancer

BackgroundNo proven targeted therapy is currently available for the treatment of triple-negative breast cancer (TNBC). Epidermal growth factor receptor (EGFR) is frequently overexpressed in TNBC. We studied the activity of EGFR antagonists alone, and in combination with chemotherapy, in TNBC cell lines.Materials and methodsEGFR and phosphorylated EGFR were measured by enzyme-linked immunosorbent assay. Sensitivity to EGFR inhibitors alone and in combination with chemotherapy was assessed. Effects of gefitinib on EGFR signalling and cell cycle were also examined.ResultsEGFR was overexpressed in the TNBC compared with the human epidermal growth factor receptor 2 (HER-2)-positive cell lines. Phosphorylation of EGFR was detected in the TNBC cells in response to epidermal growth factor stimulation and was blocked by gefitinib treatment. However, the TNBC cell lines were less sensitive to EGFR inhibition than the HER-2-positive cell lines. Response to gefitinib was associated with reduced phosphorylation of both mitogen activated protein kinase (MAPK) and Akt and induction of G₁ arrest. Gefitinib enhanced response to both carboplatin and docetaxel in the TNBC cells, and the triple combination of gefitinib, carboplatin and docetaxel was synergistic.ConclusionsAlthough the TNBC cells are less sensitive to EGFR inhibition than the HER-2-positive cell lines, gefitinib enhanced response to chemotherapy. Gefitinib combined with carboplatin and docetaxel warrants further investigation in TNBC.     

三阴性乳腺癌靶向治疗策略

目的:总结近期国内外三阴性乳腺癌的靶向治疗研究进展。方法:应用Medline、Pub Med、Web of science、CNKI数据库,以"三阴性乳腺癌、基底样乳腺癌和靶向治疗"为关键词,搜索近期发表的相关临床研究。共纳入文献30篇。结果:大量临床试验发现,靶向表皮生长因子受体(EGFR)抑制药西妥昔单抗(单克隆抗体)能明显提高TNBC患者的总反应率(ORR)、无进展生存期(PFS)、总生存期(OS)或临床获益(CB);血管内皮生长因子(VEGF)抑制药贝伐珠单抗(单克隆抗体)不能延长患者OS,但能显著延长MBC/ABC患者的PFS和ORR,索拉非尼(小分子抑制剂)能改善TNBC患者的PFS;腺苷核糖聚合酶(PARP)抑制药olaparib,能使BRCA1/2基因突变的TNBC患者获益。结论:随着对TNBC生物学行为的深入研究,新的靶点不断被发现、新的靶向药物陆续面市,使TNBC治疗策略更完善。     

Triple negative breast cancer: therapeutic and prognostic implications

Triple negative breast cancers (TNBC) lack oestrogen receptor (ER), progesterone receptor (PR), nor over-express human epidermal growth factor receptor 2 (HER2). Epidemiologic studies demonstrate that women diagnosed with TNBC manifest a significantly different set of clinic-pathologic features and risk factors when compared to women with other subtypes of breast cancer. They are associated with poor prognosis, as defined by low five-year survival. To date many studies have examined the utility of traditional chemotherapy for the treatment of patients with TNBC and have confirmed the benefits of these agents in both the adjuvant and neoadjuvant settings. Targeted therapy options involving PARP1 and EGFR inhibition, are currently in different phases of development and will hopefully change the paradigm of how patients with TNBC are treated. The present commentary aims to summarize the latest findings on chemotherapy in the treatment of TNBC in both the neoadjuvant and adjuvant setting and explore the ongoing development of newer targeted agents.     

PARP inhibitors in breast cancer: Bringing synthetic lethality to the bedside

Individuals with breast and ovarian cancer susceptibility gene 1 (BRCA1) or BRCA2 germline mutations have a significantly increased lifetime risk for breast and ovarian cancers. BRCA‐mutant cancer cells have abnormal homologous recombination (HR) repair of DNA. In these tumors, the base excision repair (BER) pathway is important for cell survival. The poly(adenosine diphosphate‐ribose) polymerase (PARP) enzymes play a key role in BER, and PARP inhibitors are effective in causing cell death in BRCA‐mutant cells while sparing normal cells—a concept called synthetic lethality. PARP inhibitors are the first cancer therapeutics designed to exploit synthetic lethality. Recent clinical trials in BRCA‐mutant, metastatic breast cancer demonstrated improved outcomes with single‐agent PARP inhibitors (olaparib and talazoparib) over chemotherapy. However, resistance to PARP inhibitors remains a challenge. Primarily due to myelosuppression, the combination of PARP inhibitors with chemotherapy has been difficult. Novel combinations with chemotherapy, immunotherapy, and other targeted therapies are being pursued. In this review, the authors discuss current knowledge of PARP inhibitors in BRCA‐mutant breast cancer and potential future directions for these agents. Cancer 2018;124:2498‐506 . © 2018 American Cancer Society.     

Clinical correlates of 'BRCAness' in triple-negative breast cancer of patients receiving adjuvant chemotherapy

BackgroundWe have previously reported an array comparative genomic hybridization profile that identifies triple-negative breast cancers (TNBC), with BRCA1 dysfunction and a high sensitivity to intensified dose bifunctional alkylating agents. To determine the effect of conventional-dose chemotherapy in patients with this so-called BRCA1-like profile, clinical characteristics and survival were studied in a large group of TNBC patients.Patients and methodsDNA was isolated and BRCA1-like status was assessed in 101 patients with early-stage TNBC receiving adjuvant cyclophosphamide-based chemotherapy. Clinical characteristics and survival were compared between BRCA1-like and non-BRCA1-like groups.ResultsSixty-six tumors (65%) had a BRCA1-like profile. Patients with BRCA1-like tumors tended to be younger and had more often node-negative disease (P = 0.06 and P = 0.03, respectively). Five-year recurrence-free survival was 80% for the BRCA1-like group and 75% for the non-BRCA1-like group (P = 0.35). T stage was the only variable significantly associated with survival.ConclusionsBRCA1-like tumors share clinical features, like young age at diagnosis and similar nodal status, with breast cancers in BRCA1 mutation carriers. Their prognosis is similar to that of non-BRCA1-like tumors when conventional-dose chemotherapy is administered. TNBCs that are classified as BRCA1-like may contain a defect in homologous recombination and could, in theory, benefit from the addition of poly ADP ribose polymerase inhibitors.     

Current status and future perspectives for the treatment of triple-negative breast cancer in Japan

Triple-negative breast cancer (TNBC) is negative for all three markers, namely the hormone sensitivity receptors: estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor receptor 2 (HER2). TNBC accounts for approximately 15% of all primary breast cancer cases. In general, patients with this disease have a higher risk of recurrence and a poorer prognosis compared with those with other subtypes of breast cancer. Patients with TNBC are defined as those for whom endocrine or anti-HER2 therapy are not indicated due to poor response. It is a heterogeneous disease group that shows various characteristics. There is a group that achieves a complete response to chemotherapy and has an excellent prognosis, a group that does not respond to chemotherapy and has a poor prognosis, and a group that has an excellent inherent prognosis and does not need chemotherapy. The subdivision of TNBC cases based on the prognosis and response to therapy is an issue for the future. In addition to classifying TNBC into basal and non-basal types by testing cytokeratin 5/6 (CK5/6) and epidemic growth factor receptors (EGFR) by the immunohistochemical staining method, Ki-67 may predict sensitivity to anticancer agents and a change in Ki-67 before and after therapy may potentially predict prognosis. Patients with a non-pathologic complete response (non-pCR) to preoperative chemotherapy have a high risk of early recurrence, and measures to deal with it are therefore needed. At present, the most commonly used perioperative chemotherapy is sequential combination therapy of an anthracycline drug and a taxane drug; however, it is limited because the pathologic complete response(pCR)rates following preoperative chemotherapy range from 30 to 40%. There is also an urgent need to develop a regimen that will overcome this problem. In association with BRCA gene mutations, sensitivity to DNA-damaging anticancer agents may lead to promising therapies. However, unfortunately, the use of DNA-damaging agents such as cisplatin and carboplatin is not covered by health insurance in Japan. Various new molecular targeted drugs aimed at blocking cell proliferation factors are expected to be developed in the future. Here we have summarized the current status and issues based on the clinical experience with the diagnosis and treatment of TNBC.     

Overview of recent advances in metastatic triple negative breast cancer

Metastatic triple negative breast cancer (TNBC) has an aggressive phenotype with a predilection for visceral organs and brain. Best responses to chemotherapy are predominately in the first line. Recent studies have demonstrated improved progression free survival with the combination of atezolizumab/pembrolizumab and chemotherapy in programmed death-ligand 1 positive metastatic TNBC. However, a recent trial in a similar population showed no benefit for atezoli-zumab and paclitaxel which led to a Food and Drug Administration alert. Two phase III trials (OLYMPIAD and BROCADE3) demonstrated a benefit in progression free survival (PFS) but not overall survival in patients with BRCA-associated metastatic TNBC treated with Olaparib or Talazoparib respectively. For those treated with Talazoparib, the time to deterioration in health related-quality of life was also longer compared to chemotherapy. The BROCADE3 trial demonstrated that the combination of a platinum and veliparib increased PFS in first-line metastatic TNBC but at the cost of increased toxicity. There are no head-to-head comparisons of a poly (adenosine diphosphate-ribose) polymerase inhibitors (PARPi) and platinums. There are unanswered questions regarding the role of PARPi maintenance after platinum therapy as is standard of care in BRCA-associated ovarian cancer. Other areas of therapeutic interest include targeting aberrations in the phosphoinositide 3-kinase pathway, protein kinase B, mammalian target of rapamycin or utilising antibody drug conjugates. This review focusses on recent and emerging therapeutic options in metastatic TNBC. We searched PubMed, clinicaltrials.gov and recent international meetings from American Society of Clinical Oncology, San Antonio Breast Cancer Conference and the European Society of Medical Oncology.     

ERCC1 Expression in Metastatic Triple Negative Breast Cancer Patients Treated with Platinum-Based Chemotherapy

Background: Possible targeted therapies for metastatic triple negative breast cancer (TNBC) include cytotoxic chemotherapy that causes interstrand breaks (platinum-based drugs). The excision repair cross-complementation 1 (ERCC1) enzyme plays an essential role in the nucleotide excision repair pathway, removing platinum-induced DNA adducts and contributing to cisplatin resistance. Detecting ERCC1 overexpression is important in considering treatment options for metastatic TNBC, including individualized approaches to therapy, and may facilitate improved responses or reduction of unnecessary toxicity. We hypothesized that assigning cisplatin based on pretreatment ERCC1 expression would improve response and survival. This study was conducted to assess the impact of ERCC1 expression on PFS, OS and response rates in metastatic triple negative breast cancer patients treated with platinum-based chemotherapy. Methods: From June 2012 to November 2013, 52 metastatic triple negative breast cancer patients were enrolled. ERCC1 protein expression was detected from pretreatment biopsies by Immunohistochemistry. All patients received cisplatin plus paclitaxel. The primary end point was the impact of ERCC1 expression on PFS and OS. Results: 34 patients (65.4%) showed positive ERCC1 expression while 18 (34.6%) proved negative. Positive ERCC1 expression was associated with short PFS (median, 5 months vs. 7 months; P = 0.043), short OS (median, 9 months vs. 11 months; P = 0.033) and poor response to cisplatin based chemotherapy (P = 0.046). Conclusions: This prospective study further validated ERCC1 as a reliable biomarker for customized chemotherapy in metastatic triple negative breast cancer patients. High expression of ERCC1 was thereby fond to be significantly associated with poor outcome in patients treated with platinum based chemotherapy.     

PARP Inhibitors in Breast Cancer: Latest Evidence

Purpose of Review

Breast cancer treatment continues to evolve as targeted therapeutic strategies are developed for the various molecular subtypes of breast cancer. The PARP inhibitors represent a novel targeted therapy for tumors with defective homologous recombination DNA repair. These agents may become standard new treatment options for patients harboring BRCA1/2 mutations and show promise in BRCA1/2 wild-type patients with triple-negative breast cancers, which are treated predominantly with traditional cytotoxic chemotherapy. This review will discuss the results of clinical trials of these agents in breast cancer as well as important ongoing and anticipated trials.

Recent Findings

Recent reports support the use of olaparib monotherapy in BRCA1/2-mutated metastatic cancer. Results of PARP inhibitor combinations with chemotherapy have been mixed. The addition of veliparib failed to improve pathological complete response rates in patients with early-stage triple-negative breast cancer treated with carboplatin (AUC6) and paclitaxel followed by doxorubicin plus cyclophosphamide in a phase 3 trial. The PARP inhibitors talazoparib and olaparib are currently being tested in the neoadjuvant and adjuvant settings but impact on survival measures will likely take years prior to reporting in these early-stage breast cancer studies.

Summary

While data from the first phase 3 trials of PARP inhibitors in breast cancers are encouraging in patients with germline deleterious BRCA1/2 mutations, continued work is needed to elucidate their utility beyond the BRCA1/2-mutated population as has been possible in ovarian cancer. Additionally, defining the ideal population and setting for combination treatment remains a challenge and has been limited by synergistic toxicities.

     

Targeting Epidermal Growth Factor Receptor in triple negative breast cancer: New discoveries and practical insights for drug development

Triple negative breast cancer (TNBC) accounts for 10–20% of cases in breast cancer. Despite recent advances in the treatment of hormonal receptor+ and HER2+ breast cancers, there are no targeted therapies available for TNBC. Evidence supports that most patients with TNBC express the transmembrane Epidermal Growth Factor Receptor (EGFR). However, early phase clinical trials failed to demonstrate significant activity of EGFR-targeted monoclonal antibodies and/or tyrosine kinase inhibitors. Here, we review the recent discoveries related to the underlying biology of the EGFR pathway in TNBC, clinical progress to date and suggest rational future approaches for investigational therapies in TNBC.     

Role of epidermal growth factor receptor in breast cancer

Decades of research in molecular oncology have brought about promising new therapies which are designed to target specific molecules which promote tumor growth and survival. The epidermal growth factor receptor (EGFR) is one of the first identified important targets of these novel antitumor agents. Approximately half of cases of triple-negative breast cancer (TNBC) and inflammatory breast cancer (IBC) overexpress EGFR. Thus, EGFR inhibitors for treatment of breast cancer have been evaluated in several studies. However, results so far have been disappointing. One of the reasons for these unexpected results is the lack of biomarkers for predicting which patients are most likely to respond to EGFR inhibitors. Recent studies have shown that EGFR and its downstream pathway regulate epithelial-mesenchymal transition, migration, and tumor invasion and that high EGFR expression is an independent predictor of poor prognosis in IBC. Further, recent studies have shown that targeting EGFR enhances the chemosensitivity of TNBC cells by rewiring apoptotic signaling networks in TNBC. These studies indicate that EGFR-targeted therapy might have a promising role in TNBC and IBC. Further studies of the role of EGFR in TNBC and IBC are needed to better understand the best way to use EGFR-targeted therapy??e.g., as a chemosensitizer or to prevent metastases??to treat these aggressive diseases.     

三阴性乳腺癌化疗进展

三阴性乳腺癌作为乳腺癌的一种特殊亚型,对内分泌治疗和现有靶向治疗无效,并且通常复发较早、进展迅速、预后较差。现就三阴性乳腺癌的分子分型及其临床价值、化疗药物和化疗方案以及化疗和潜在的新靶点药物联合方面的最新进展作一综述。