The role of hormonal therapy in the management of hormonal-receptor-positive breast cancer with co-expression of HER2

Approximately half of breast cancers that overexpress human epidermal growth factor receptor 2 (HER2) also express hormone receptors (HRs). Although HR positivity predicts efficacy of endocrine agents, preclinical and clinical data suggest that HER2 overexpression confers intrinsic resistance to hormonal treatment. In addition, HER2 overexpression is an independent adverse prognostic factor regardless of the hormonal status of the tumor, indicating that patients with HR+/HER2+ breast tumors might not derive a benefit from single-agent hormonal therapy. These data provided a strong rationale for exploring the targeting of both HR and HER2 signaling pathways in HR+/HER2+ breast tumors to optimize hormonal therapy and overcome resistance to anti-estrogen therapy. Results from a randomized clinical trial that combined hormonal treatment with targeted anti-HER2 therapy in postmenopausal women with HR+/HER2+ advanced breast cancer indicate that this novel dual-targeting strategy significantly improves outcomes compared with endocrine treatment alone. Nonetheless, other data suggest that it might achieve an inferior outcome compared with anti-HER2 therapy plus chemotherapy. Therefore, targeting both the HR and HER2 signaling pathways upfront might not be the most-effective therapeutic strategy in the management of HR+/HER2+ breast cancer. We discuss the clinical implication of resistance to endocrine therapy, and describe new insights into the management of HR+/HER2+ advanced breast cancer.     

HR+/HER2+晚期乳腺癌药物治疗方案选择的研究进展#br#

激素受体阳性/人表皮生长因子受体2阳性乳腺癌是一种具有独特特征的乳腺癌亚型。国内外指南建议,无论HR状态如何,含抗HER2治疗的联合方案(如曲妥珠单抗和帕妥珠单抗)应作为HER2+晚期乳腺癌的一线治疗。内分泌治疗可作为不能耐受化疗或化疗后患者的维持治疗。既往研究表明,HR通路与HER2通路相互作用,内分泌联合靶向治疗可有效避免肿瘤耐药。因此,内分泌联合靶向治疗是HR+/HER2+患者替代化疗的首选治疗方案。文章对HR+/HER2+乳腺癌的生物学特征、诊疗现状及未来研究方向进行综述。     

Therapeutic implications of estrogen receptor signaling in HER2-positive breast cancers

There is considerable pre-clinical and clinical evidence demonstrating that HER2-positive breast cancers that express estrogen receptor (ER) exhibit intrinsic resistance to endocrine therapy. Therefore, in general, chemotherapy in combination with HER2-directed agents is recommended for all but the smallest HER2-positive early stage breast cancers regardless of ER status. This paradigm has recently come into question when responses to neo-adjuvant HER2-directed regimens were noted to vary based on ER expression, and pathologic complete response was noted not to be prognostic for ER-positive, HER2-positive breast cancers. These and other data suggest the possibility that a subset of HER2-positive, ER-positive breast cancers are driven primarily by ER, and biologically behave more like HER2-negative, ER-positive breast cancers. Identification of this subset of HER2-positive breast cancers is essential to avoid over-treatment of patients with small HER2-positive, ER-positive breast cancers, who may be optimally treated with endocrine therapy alone, or in combination with a HER2-directed agent, thereby avoiding the use of chemotherapy. Crosstalk between the ER and HER2 pathways has been established as playing a role in both intrinsic and acquired resistance to endocrine agents. Emerging data suggests that crosstalk between these pathways is also involved in resistance to HER2-directed agents. Unraveling the role of the ER pathway in resistance to HER2-directed agents could potentially result in therapeutic approaches that can improve outcome for patients with ER-positive, HER2-positive breast cancer.     

Loss of HER2 positivity and prognosis after neoadjuvant therapy in HER2-positive breast cancer patients

BackgroundEmerging literature data are showing that a change in human epidermal growth factor receptor (HER2) status adversely affects breast cancer patient's prognosis. The aim of this study was to evaluate the prognostic impact of HER2 loss in patients with HER2-positive disease treated with neoadjuvant therapy with or without anti-HER2 agents.MethodsOne hundred and seven consecutive HER2-positive patients were identified from a prospectively maintained database. The first cohort includes 40 patients treated with chemotherapy (CT) alone. The second cohort includes 67 patients treated with neoadjuvant CT plus anti-HER2 agents (trastuzumab and/or lapatinib). HER2 expression was evaluated by immunihistochemistry or fluorescence in situ hybridization on pretreatment core biopsy and on surgical specimen after therapy.ResultsThe rates of pathologic complete response (pCR) and breast-conserving surgery were higher in the CT + anti-HER2 cohort. A loss of HER2 expression was observed in 40% of the patients with residual disease after CT alone versus 14.7% of the patients after CT + anti-HER2 agents (P = 0.019). Patients not achieving a pCR have a significant increase in the risk of relapse when compared with those achieving a pCR (hazard ratio [HR] 9.55, P = 0.028). Patients with HER2 loss tended to have a higher risk of relapse as comparing to patients with maintained HER2 positivity (HR 2.41, P = 0.063).ConclusionThe pCR is confirmed as a powerful predictor of long-term outcome. The rate of HER2 loss is higher in patients receiving neoadjuvant CT without anti-HER2 agents. HER2 status on residual disease after preoperative therapy can be helpful in selecting patients at different risk of relapse, to be included in prospective trial exploring further adjuvant therapy.     

HER2 and hormone receptor-positive breast cancer--blocking the right target

HER2-positive tumors have a worse prognosis than HER2-negative cancers. Although the standard treatment for HER2-positive metastatic breast cancer is chemotherapy and trastuzumab, the combination of aromatase inhibitors with anti-HER2 therapies has become an available strategy in patients with HER2-positive and hormone receptor-positive tumors. However, although this new treatment option is more effective than hormone therapy alone, it has not been compared with the standard chemotherapy and trastuzumab-based regimens. In fact, the activity observed in randomized clinical trials with chemotherapy and anti-HER2 therapies seems to be higher than that observed with aromatase inhibitors and trastuzumab-based or lapatinib-based therapies. In this article, we highlight the importance of considering chemotherapy and anti-HER2 therapy as the standard of care in HER2-positive and hormone receptor-positive tumors.     

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.     

Dual human epidermal growth factor receptor 2 blockade for the treatment of HER2-positive breast cancer

The introduction of trastuzumab into clinical practice changed the natural course of HER2-positive breast cancer. Currently, treatment with trastuzumab represents the standard of care for HER2-positive breast cancer and this treatment has been approved in the adjuvant, neoadjuvant, and metastatic settings. Besides trastuzumab, two other anti-HER2 agents—lapatinib and pertuzumab—have been approved for the treatment of HER2-positive advanced breast cancer. Strong biologic data support the concept of dual HER2 blockade, with different anti-HER2 agents demonstrating complementary mechanisms of action. Several neoadjuvant and metastatic studies performed in HER2-positive breast cancer using dual HER2 blockade have been proven to outperform anti-HER2 monotherapies. These dual combinations of agents represent a promising therapeutic strategy that is now reaching clinical practice. In this review we describe the results of studies utilizing dual blockade in patients with HER2-positive breast cancer.     

The role of adjuvant monoclonal antibody therapy for breast cancer: rationale and new studies

HER2 is a member of the epidermal growth factor receptor (EGFR) family of tyrosine kinases and is involved in the growth, invasion, metastasis, and prognosis of breast cancer. The rationale for prospective trials evaluating the role of anti-HER2 monoclonal antibody therapy for patients with high-risk HER2-positive resected breast cancer is based on several factors. These include 1) the relative and absolute poor prognosis of patients with node-positive, HER2-positive breast cancer; 2) the emerging data of potential importance concerning anthracyclines as a component of adjuvant therapy for patients with HER2-positive breast cancer; 3) the role of taxanes in the management of patients with HER2-positive metastatic breast cancer; and 4) the feasibility and efficacy of molecularly targeted anti-HER2 monoclonal antibody treatment alone or in combination with chemotherapy for patients with advanced breast cancer.     

Trastuzumab as first-line therapy in HER2-positive metastatic breast cancer patients

Trastuzumab is a humanized monoclonal antibody against the extracellular domain of hEGF receptor-2 (HER2). Trastuzumab in combination with chemotherapy has proven efficacy in treating both early and metastatic HER2-positive breast cancer. In the metastatic setting, the addition of trastuzumab to chemotherapy is associated with a statistically significant longer time to disease progression, higher rate of objective response and improvement in overall survival. Trastuzumab efficacy is not influenced by hormone receptor status, but differences in median overall survival exist between HER2-positive and HER2-negative states. Reassessment of the benefit of re-exposing patients with metastatic breast cancer to trastuzumab following relapse in the adjuvant setting is necessary. Ongoing research into new HER2-targeted therapies and trials involving combination anti-HER2 drug therapy without chemotherapy show promise. This review is focused on the available results obtained with the use of trastuzumab in the subset of HER2-positive breast cancer patients with metastatic disease.     

HER2蛋白活化在HR阳性乳腺癌内分泌耐药中作用的研究进展

激素受体(hormone receptor,HR)阳性乳腺癌约占全部乳腺癌患者的70%,其重要治疗方式为抑制HR通路的内分泌治疗,此型乳腺癌预后虽然相对较好,但仍有30%~40%患者出现内分泌耐药,目前尚未解决。通路间的交联作用在内分泌耐药中发挥重要作用,受体磷酸化是各通路发挥作用的前提,越来越多研究表明人表皮生长因子受体2(human epidermal growth factor receptor 2,HER2)的活化与激素受体阳性乳腺癌内分泌耐药相关,故充分了解HER2蛋白活化与内分泌耐药间的关系,对延缓内分泌耐药具有重要意义。因此本文将顺序阐述HER2蛋白的表达、生物学特性、检测、活化以及HER2蛋白活化在乳腺癌内分泌耐药中的作用,为HR阳性乳腺癌的治疗提供思路。     

T1期HER2阳性乳腺癌患者临床特征及抗HER2靶向治疗对预后的影响分析

目的 总结T1期HER2阳性乳腺癌患者的临床病理特征,并分析抗HER2靶向治疗对预后的影响.方法 选取T1期HER2阳性乳腺癌患者50例,总结其临床病理特征,运用统计学方法分析影响患者预后的因素及抗HER2靶向治疗与患者预后关系.结果50例患者中T1a~1b期共13例(26%),T1c期共37例(74%),共4例出现复发转移,无死亡,总随访时间6~36个月,中位随访时间22个月;不同组织学分级、临床分期、脉管是否浸润、腋窝淋巴结是否转移、Ki-67是否为阳性、是否接受抗HER2靶向治疗的T1a~1b期与T1c期患者例数比较,差异有统计学意义(P﹤0.05);与未接受抗HER2靶向治疗患者(无病生存率为89.7%)相比,接受完整抗HER2靶向治疗患者3年内无患者出现复发转移(无病生存率为100.0%),差异有统计学意义(P=0.046);脉管浸润组及腋窝淋巴结转移组中是否接受靶向治疗患者的无病生存率比较,差异有统计学意义(P﹤0.05);Cox多因素分析显示腋窝淋巴结是否转移是影响T1期HER2阳性乳腺癌患者预后的独立因素.结论 T1期HER2阳性乳腺癌患者是否有腋窝淋巴结转移是其预后的独立影响因素,抗HER2靶向治疗对T1期HER2阳性乳腺癌伴随脉管转移或腋窝淋巴结转移患者预后较好.     

HER2-positive breast cancer: from trastuzumab to innovatory anti-HER2 strategies

Overexpression of HER2 is encountered in approximately 20% of invasive breast cancers. It is an independent adverse prognostic factor and, more importantly, it is currently the best predictive factor for the activity of trastuzumab, an anti-HER2 monoclonal antibody (MoAb), which has revolutionized the treatment of this breast cancer subgroup. Increasing knowledge of molecular pathways involving the HER family of growth factor receptors has paved the way toward new efficient targeted therapies. Herein, we will review the targeted therapies of clinical importance for HER2-positive breast cancer, which include anti-HER2 MoAbs and tyrosine kinase inhibitors that directly interfere at the receptor level. Clinicians are still facing many uncertainties concerning the optimal use of these new agents, and scientists are working on dissecting the mechanisms of resistance developed by HER2-positive cancer cells. Interesting perspectives in the treatment of HER2-positive breast cancer will be discussed. They consist of designing HER2 peptide-based vaccines, targeting downstream pathway molecules beyond the membrane receptor, and exploring synergistic antineoplasic strategies.     

不同激素状态的HER2阳性晚期乳腺癌复发转移特征及生存分析

 目的 探讨不同HR状态的HER2阳性晚期乳腺癌患者的复发转移特征、预后及解救曲妥珠单抗治疗疗效的差异。方法 回顾性分析237名HER2阳性晚期乳腺癌患者的临床病理学资料，根据HR状态分为HR+/HER2+组和HR-/HER2+组，对两组间临床病理学特征、复发转移特点、预后及解救曲妥珠单抗治疗疗效进行分析比较。结果 与HR-/HER2+相比，HR+/HER2+多为绝经前患者，临床分期以Ⅰ~Ⅱ期为主，T分期更早，较少发生腋窝淋巴结转移。在总体复发转移部位上HR+/HER2+者更易发生骨转移，较少发生肺转移。HR+/HER2+组中位总生存时间34（5~102）月，HR-/HER2+组为29（3~70）月，两组间差异有统计学意义。接受解救曲妥珠单抗联合化疗的患者，ER<50%者达PR者占68.6%，ER≥50%者占46.2%，差异有统计学意义（P=0.037）。多因素分析结果显示ER状态是HR+/HER2+晚期乳腺癌的独立预后因素；肝转移、解救抗HER2靶向治疗是HR-/HER2+晚期乳腺癌的独立预后因素。结论 与HR-/HER2+患者相比，HR+/HER2+患者多发生骨转移，较少发生肺转移；预后较好；ER阳性细胞数所占比例较高的患者解救曲妥珠单抗治疗疗效较差。     

Biomarkers for HER2-positive metastatic breast cancer: Beyond hormone receptors

The overexpression of human epidermal growth factor receptor-2 (HER2) results in a biologically and clinically aggressive breast cancer (BC) subtype. Since the introduction of anti-HER2 targeted agents, survival rates of patients with HER2-positive metastatic BC have dramatically improved. Currently, although the treatment decision process in metastatic BC is primarily based on HER2 and hormone-receptor (HR) status, a rapidly growing body of data suggests that several other sources of biological heterogeneity may characterize HER2-positive metastatic BC. Moreover, pivotal clinical trials of new anti-HER2 antibody-drug conjugates showed encouraging results in HER2-low metastatic BC, thus leading to the possibility, in the near future, to expand the pool of patients suitable for HER2-targeted treatments. The present review summarizes and puts in perspective available evidence on biomarkers that hold the greatest promise to become potentially useful tools for optimizing HER2-positive metastatic BC patients' prognostic stratification and treatment in the next future. These biomarkers include HER2 levels and heterogeneity, HER3, intrinsic molecular subtypes by PAM50 analysis, DNA mutations, and immune-related factors. Molecular discordance between primary and metastatic tumors is also discussed.     

Trastuzumab in small tumours and in elderly women

Results of trials assessing the role of trastuzumab in the adjuvant setting in early breast cancer have brought a new standard of treatment to clinical practice. Nevertheless, some groups of patients are underrepresented in these trials and thus therapy should be planned based on incomplete information or lack of solid data. Two of these groups are high-risk HER2+ small tumours (<1 cm) and elderly patients. In this review we aimed at addressing the most relevant data about these two populations underrepresented in clinical trials. HER2 overexpression or amplification confers a bad prognosis in patients with small breast tumours. Mammographic screening is increasing the early diagnosis. Taking into account that specific targeted adjuvant treatment can avoid relapses in 50% of HER2-positive patients, about 2 to 7% of relapses from small tumours could be avoided with the use of this treatment. Randomized and non-randomized trials support the idea that adjuvant therapies could improve clinical outcomes of ?1 cm tumours. Adding a HER2-targeted treatment to chemotherapy may improve efficacy. Some recent data in the neo-adjuvant context suggest that, in some patients, aggressive chemotherapy treatment could be properly substituted by HER2-targeted therapy. In elderly women with HER2+ breast cancer, trastuzumab should be considered for adjuvant-treatment, particularly in those at higher risk of relapse, lack of extra risk factors for trastuzumab-associated cardiotoxicity, and having a prolonged estimated life expectancy. In addition to traditional anthracycline–based combinations commonly used in younger women, other options are the use of sequential chemotherapy, non-anthracycline containing regimes plus anti-HER2 therapies, combinations with hormonotherapy, or even anti-HER2 agents alone.     

Emerging approaches for treating HER2-positive metastatic breast cancer beyond trastuzumab

Because metastatic breast cancer (MBC) is incurable in most cases, the goals of treatment are improvement in quality of life, management of symptoms, and prolonged survival. The human epidermal growth factor receptor 2 (HER2) is overexpressed in up to 30% of breast tumors, and before the development of HER-targeted therapy, HER2 positivity was predictive of poorer clinical outcomes. Trastuzumab and pertuzumab (anti-HER2 monoclonal antibodies), lapatinib (a small molecule inhibitor of HER2 and the epidermal growth factor receptor [EGFR]) are approved for treating HER2-positive MBC in the United States. Although trastuzumab plus chemotherapy is currently regarded as the first-line standard of care for HER2-positive MBC, it is not without shortcomings; these include its association with certain adverse events (e.g. cardiotoxic effect) and development of resistance. A number of investigational agents that target HER2 and other members of that receptor family are in clinical development for patients with HER2-positive MBC whose disease has progressed on trastuzumab. In addition, in an effort to overcome treatment resistance, clinical trials are evaluating combination therapy (investigational HER-targeted agents with trastuzumab or lapatinib). This review discusses recently completed and ongoing phase II and III clinical trials of investigational HER-targeted agents in the setting of trastuzumab-progressive, HER2-positive MBC.     

Progression and treatment of HER2-positive breast cancer

Purpose

Approximately 20–30% of breast cancer tumors overexpress or amplify human epidermal growth factor receptor 2 (HER2). The role of this receptor in the progression of HER2+ breast cancer and resistance to certain anticancer monotherapies was investigated. The results of several pre-clinical and clinical trials, with the aim of determining the most safe and effective course of treatment for HER2+ breast cancer, were also thoroughly examined.

Methods

A thorough search of databases including Pubmed, Springer, and The American Society of Clinical Oncology was performed, and pertinent studies were identified. The most relevant studies were preclinical, phase II, and III clinical trials identifying the function of the HER2 receptor in HER2+ breast cancer progression, as well as studies assessing the efficacy of monotherapy and combination therapy in the treatment of this aggressive form of cancer.

Results

The HER2 receptor belongs to a family of receptors that consists of four cell-surface receptors (HER1-4) that share strong homology with the epidermal growth factor receptor (EGFR). All HER receptors interact with specific types of ligands to induce receptor activation, except for HER2, for which no known ligand has yet been identified. HER2 is activated by forming dimers with other HER receptors, and this results in a stronger and more prolonged signal transduction event. When expressed at normal levels, HER2 regulates cell growth, differentiation, and survival. However, under pathological conditions of HER2 overexpression, numerous HER2 heterodimers are formed resulting in aggressive tumor growth. Therefore, the prognosis associated with HER2-positive breast cancer is usually poor. A specific cohort of patients with breast cancer whose tumors test both hormone receptor (estrogen receptor [ER] and progesterone receptor [PR]) and HER2 positive have been found to be resistant to targeted hormone therapy. Studies investigating the etiology of this resistance have found that the cell membrane estrogen receptor communicates with HER2 in promoting the release of ER coactivators that cause the endocrine drug and selective estrogen receptor modulator, tamoxifen, to act as an agonist rather than an antagonist of the hormone estrogen. Thus, research has directed its inquiry toward the development of therapies specifically targeting HER2. The development of trastuzumab, a recombinant monoclonal antibody against HER2, initially proved to be a well-tolerated first line of treatment. However, in the long-term patients, trastuzumab was shown to develop resistance to this monotherapy. Therefore, research on HER2 positive breast cancer has focused on the study of different anti-HER2 combination therapies over the past decade.

Conclusions

While the development and approval of the HER2-targeted recombinant monoclonal antibody trastuzumab (Herceptin) has been efficacious in slowing HER2 cancer progression, combining this and other anti-HER2 therapy with either chemotherapy or endocrine therapy has proven more effective in improving overall and progression free survival.     

曲妥珠单抗治疗HER2+乳腺癌的临床进展

临床研究显示曲妥珠单抗与化疗联合用于人表皮生长因子受体2(HER2)+转移性乳腺癌的治疗以及早期乳腺癌的新辅助和辅助治疗,能显著延长患者的生存时间.其与内分泌治疗联合治疗HER2+且雌激素受体阳性的转移性乳腺癌,疗效优于单纯内分泌治疗.曲妥珠单抗联合其他靶向治疗药物,能够逆转肿瘤对曲妥珠单抗的耐药.疾病进展后继续应用曲妥珠单抗仍可使患者生存受益.