Mechanisms of resistance to anti-epidermal growth factor receptor inhibitors in metastatic colorectal cancer

The prognosis of patients with metastatic colorectal cancer (mCRC) remain poor despite the impressive improvement of treatments observed over the last 20 years that led to an increase in median overall survival from 6 mo, with the only best supportive care, to approximately 30 mo with the introduction of active chemotherapy drugs and targeted agents. The monoclonal antibodies (moAbs) cetuximab and panitumumab, directed against the epidermal growth factor receptor (EGFR), undoubtedly represent a major step forward in the treatment of mCRC, given the relevant efficacy in terms of progression-free survival, overall survival, response rate, and quality of life observed in several phase III clinical trials among different lines of treatment. However, the anti-EGFR moAbs were shown only to be effective in a subset of patients. For instance, KRAS and NRAS mutations have been identified as biomarkers of resistance to these drugs, improving the selection of patients who might derive a benefit from these treatments. Nevertheless, several other alterations might affect the response to these drugs, and unfortunately, even the responders eventually become resistant by developing secondary (or acquired) resistance in approximately 13-18 mo. Several studies highlighted that the landscape of responsible alterations of both primary and acquired resistance to anti-EGFR drugs biochemically converge into MEK-ERK and PIK3CA-AKT pathways. In this review, we describe the currently known mechanisms of primary and acquired resistance to anti-EGFR moAbs together with the various strategies evaluated to prevent, overcame or revert them.

Clinical efficacy and drug resistance of anti-epidermal growth factor receptor therapy in colorectal cancer

Colorectal cancer(CRC) ranked third in cancer related death and its incidence has been increasing worldwide. In recent decades important therapeutic advances have been developed in treatment of metastatic CRC(mCRC), such as monoclonal antibodies against epidermal growth factor receptor(anti-EGFR), which provided additional clinical benefits in mCRC. However, anti-EGFR therapies have limited usage due to approximately 95% of patients with KRAS mutated mCRC do not response to anti-EGFR treatment. Thus, KRAS mutation is predictive of nonresponse to anti-EGFR therapies but it alone is not a sufficient basis to decide who should not be received such therapies because; approximately fifty percent(40%-60%) of CRC patients with wild-type KRAS mutation also have poor response to anti-EGFR based treatment. This fact leads us to suspect that there must be other molecular determinants of response to anti-EGFR therapies which have not been identified yet. Current article summarizes the clinical efficacy of anti-EGFR therapies and also evaluates its resistance mechanisms.

Growth factor receptors and related signalling pathways as targets for novel treatment strategies of hepatocellular cancer

Growth factors and their corresponding receptors are commonly overexpressed and/or dysregulated in many cancers including hepatocellular cancer （HCC）. Clinical trials indicate that growth factor receptors and their related signalling pathways play important roles in HCC cancer etiology and progression, thus providing rational targets for innovative cancer therapies. A number of strategies including monoclonal antibodies, tyrosine kinase inhibitors （＂small molecule inhibitors＂） and antisense oligonucleotides have already been evaluated for their potency to inhibit the activity and downstream signalling cascades of these receptors in HCC. First clinical trials have also shown that multi-kinase inhibition is an effective novel treatment strategy in HCC. In this respect sorafenib, an inhibitor of Raf-, VEGF- and PDGF-signalling, is the first multi-kinase inhibitor that has been approved by the FDA for the treatment of advanced HCC. Moreover, the serine-threonine kinase of mammalian target of rapamycin （mTOR） upon which the signalling of several growth factor receptors converge plays a central role in cancer cell proliferation, roTOR inhibition of HCC is currently also being studied in preclinical trials. As HCCs represent hypervascularized neoplasms, inhibition of tumour vessel formation via interfering with the VEGF/VEGFR system is another promising approach in HCC treatment. This review will summarize the current status of the various growth factor receptor-based treatment strategies and in view of the multitude of novel targeted approaches, the rationale for combination therapies for advanced HCC treatment will also be taken into account.

Treatment of gastrointestinal neuroendocrine tumors with inhibitors of growth factor receptors and their signaling pathways: Recent advances and future perspectives

The limited efficacy of conventional cytotoxic treatment regimes for advanced gastrointestinal neuroendocrine cancers emphasizes the need for novel and more effective medical treatment options. Recent findings on the specific biological features of this family of neoplasms has led to the development of new targeted therapies, which take into account the high vascularization and abundant expression of specific growth factors and cognate tyrosine kinase receptors. This review will briefly summarize the status and future perspectives of antiangiogenic, mTOR- or growth factor receptor-based pharmacological approaches for the innovative treatment of gastrointestinal neuroendocrine tumors. In view of the multitude of novel targeted approaches, the rationale for innovative combination therapies, i.e. combining growth factor (receptor)-targeting agents with chemo- or biotherapeutics or with other novel anticancer drugs such as HDAC or proteasome inhibitors will be taken into account.

Epidermal growth factor receptor inhibitors in colorectal cancer treatment: What's new?

Colorectal cancer constitutes one of the most common malignancies and the second leading cause of death from cancer in the western world representing one million new cases and half a million deaths annually worldwide. The treatment of patients with metastatic colon cancer comprises different regimens of chemotherapeutic compounds （fluoropyrimidines, irinotecan and oxaliplatin） and new targeted therapies. Interestingly, most recent trials that attempt to expose patients to all five-drug classes （fluoropyrimidines, irinotecan, oxaliplatin, bevacizumab and cetuximab） achieve an overall survival well over 2 years. In this review we will focus on the main epidermal growth factor receptor inhibitors demonstrating clinical benefit for colorectal cancer mainly cetuximab, panitumumab, erlotinib and gefltinib. We will also describe briefly the molecular steps that lie beneath them and the different clinical or molecular mechanisms that are reported for resistance and response.

Targeting the insulin-like growth factor pathway in hepatocellular carcinoma

Hepatocellular carcinoma(HCC) is the third leading cause of cancer-related deaths worldwide. Only 30%-40% of the patients with HCC are eligible for curative treatments, which include surgical resection as the first option, liver transplantation and percutaneous ablation. Unfortunately, there is a high frequency of tumor recurrence after surgical resection and most HCC seem resistant to conventional chemotherapy and radiotherapy. Sorafenib, a multi-tyrosine kinase inhibitor, is the only chemotherapeutic option for patients with advanced hepatocellular carcinoma. Patients treated with Sorafenib have a significant increase in overall survival of about three months. Therefore, there is an urgent need to develop alternative treatments. Due to its role in cell growth and development, the insulin-like growth factor system is commonly deregulated in many cancers. Indeed, the insulin-like growth factor(IGF) axis has recently emerged as a potential target for hepatocellular carcinoma treatment. To this aim, several inhibitors of the pathway have been developed suchas monoclonal antibodies, small molecules, antisense oligonucleotides or small interfering RNAs. However recent studies suggest that, unlike most tumors, HCC development requires increased signaling through insulin growth factor Ⅱ rather than insulin growth factor Ⅰ. This may have great implications in the future treatment of HCC. This review summarizes the role of the IGF axis in liver carcinogenesis and the current status of the strategies designed to target the IGF-Ⅰ signaling pathway for hepatocellular carcinoma treatment.

Effect of blocking IGF-I receptor on growth of human hepatocellular carcinoma cells

AIM： To study the expression level and localization of insulin-like growth factor -Ⅰ receptor （IGF-IR） in HepG2 cells and Chang liver cells, and to observe the effect of anti-IGF-IR monoclonal antibody （αIR3） on the growth of HepG2 cells. METHODS： The expression of IGF-IR in HepG2 cells and Chang liver cells was detected by immunohistochemistry. The influences of αIR3 on proliferation and apoptosis were examined by the 3- （4, 5-dimethylthiazol-2-yl）-2, 5- diphenyltetrazolium bromide （MTT） assay and electron microscopy, respectively. Flow cytometry （FCM） was applied for the analysis of cell cycle and apoptosis was observed under electron microscope. RESULTS： IGF-IR was located in the membranes of both HepG2 and Chang liver cell lines, and the expression level of IGF-IR was higher in HepG2 cells than in Chang liver cells. Treated with 0.1 μg/mL αIR3 for 48 h in vitro, the cell growth index （GI） of HepG2 cells was significantly higher than that of control （103.41% ys 100%, P 〈 0.01）. However, the αIR3 for 24 h at final concentration of 4.0 μg/mL made the GI of HepG2 cells lower than that of control （93.37% vs 100%, P 〈 0.01）. Compared with control, treated with αIR3 for 48 h at final concentrations ranging from 2.0 μg/mL to 4.0 μg/mL markedly reduced the GIs of HepG2 cells （97.63%, 97.16%, 95.13%, 92.53% vs 100%, P 〈 0.05 or P 〈 0.01）, treated with αIR3 for 72 h at final concentrations ranging from 0.2 μg/mL to 4.0 μg/mL decreased the GIs of HepG2 cells obviously （95%, 91.63%, 90.77%, 89.84%, 88.51% vs 100%, P 〈 0.01）, and treated with αIR3 for 96 h at final concentrations ranging from 0.5 μg/mL to 4.0 μg/mL made GIs of HepG2 cells lower significantly （88.86%, 83.97%, 79.81%, 77.24%, 70.51% vs 100%, P 〈 0.05or P 〈 0.01）. Moreover, treated with αIR3 from 24 h to 96 h at final concentrations ranging from 0.2 μg/mL to 4.0 μg/mL reduced the GI of HepG2 cells from 97.63% to 70.51% in a dose- and time-dependent manner. Also, αIR3 treatment for 72 h at final concentration from 0.5 μg/mL to 2.0 μg/mL increased the proportion of G0/G1 phase cells（61.73%, 67.1%, 83.7%,76.87% vs 44.47%, P 〈 0.01） and significantly decreased that of S phase cells（28.63%, 25.13%, 15.63%, 23.13% vs 53.17%, P 〈 0.01）, in contrast to the proportion of G2/M phase cells. The apoptotic rates of HepG2 cells were increased more than that of control （7.83%, 16.13%, 21.1%, 37.73% vs 4.13%, P 〈 0.01）. CONCLUSION： The malignant cell phenotype of human hepatocarcinoma cell is related to overexpression of IGF- IR. The blockage of IGF-IR with αIR3 may contribute to the inhibition of proliferation and induction of apoptosis in HepG2 cells.

Beyond KRAS:Predictive factors of the efficacy of anti-EGFR monoclonal antibodies in the treatment of metastatic colorectal cancer

Systematic analysis of the epidermal growth factor receptor(EGFR)pathway revealed that biomarkers could be used to predict the response to and outcome of antiEGFR therapies in patients affected by metastatic colorectal cancer.We have conducted a review on the most recent findings and advances on this topic.To this aim,we searched the PubMed database for articles devoted to predictive and prognostic biomarkers for patients administered cetuximab-and panitumumab-based therapies.Here we review the state of the art and the controversies about the molecular factors known to be predictors of the efficacy of anti-EGFR therapy,namely,KRAS,BRAF,NRAS,PI3KCA and PTEN,and we discuss their prognostic value in colorectal cancer patients.

Targeting Transforming Growth Factor-<i>β</i>(TGF-<i>β</i>) in Cancer and Non-Neoplastic Diseases

Transforming growth factor-β?(TGF-β) superfamily is a key player in the regulation of a wide variety of physiological processes from development to pathogenesis. Since the discovery of the prototypic member, TGF-β, almost three decades ago, there have been tremendous advances in our understanding of its complex biology. TGF-β?misregulation has been implicated in the pathogenesis of a variety of diseases, including cancer with a direct role in facilitating metastasis, fibrosis and inflammation. Consequently, TGF-β?is currently explored as a prognostic candidate biomarker of tumor invasiveness and metastasis;and it offers an attractive target for cancer therapy. Several anti-TGF-β?approaches, such as TGF-β?antibodies, antisense oligonucleotides and small molecules inhibitors of TGF-β?type 1 receptor kinase, have shown great promise in the preclinical studies. Here, we consider why the TGF-βsignaling pathway is a drug target, the potential clinical applications of TGF-β?inhibition, the issues arising with anti-TGF-β?therapy and how these might be adopted using personalized approaches with a special care for patient selection and timing of therapy so that we may bring forward all the potentials of targeting this pathway for therapeutic uses in both cancer, preferentially in combination therapy, and non-neoplastic diseases.

^(125)I-labeled anti-b FGF monoclonal antibody inhibits growth of hepatocellular carcinoma

AIM: To investigate the inhibitory efficacy of 125I-labeled anti-basic fibroblast growth factor (bFGF) monoclonal antibody (mAb) in hepatocellular carcinoma (HCC).METHODS: bFGF mAb was prepared by using the 1G9B9 hybridoma cell line with hybridization technology and extracted from ascites fluid through a Protein G Sepharose affinity column. After labeling with 125I through the chloramine-T method, bFGF mAb was further purified by a Sephadex G-25 column. Gamma radiation counter GC-1200 detected radioactivity of 125I-bFGF mAb. The murine H22 HCC xenograft model was established and randomized to interventions with control (phosphate-buffered saline), 125I-bFGF mAb, 125I plus bFGF mAb, bFGF mAb, or 125I. The ratios of tumor inhibition were then calculated. Expression of bFGF, fibroblast growth factor receptor (FGFR), platelet-derived growth factor, and vascular endothelial growth factor (VEGF) mRNA was determined by quantitative reverse transcriptase real-time polymerase chain reaction.RESULTS: The purified bFGF mAb solution was 8.145 mg/mL with a titer of 1:2560000 and was stored at -20 °C. After coupling, 125I-bFGF mAb was used at a 1: 1280000 dilution, stored at 4 °C, and its specific radioactivity was 37 MBq/mg. The corresponding tumor weight in the control, 125I, bFGF mAb, 125I plus bFGF mAb, and 125I-bFGF mAb groups was 1.88 ± 0.25, 1.625 ± 0.21, 1.5 ± 0.18, 1.41 ± 0.16, and 0.98 ± 0.11 g, respectively. The tumor inhibition ratio in the 125I, bFGF mAb, 125I plus bFGF mAb, and 125I-bFGF mAb groups was 13.6%, 20.2%, 25.1%, and 47.9%, respectively. Growth of HCC xenografts was inhibited significantly more in the 125I-bFGF mAb group than in the other groups (P < 0.05). Expression of bFGF and FGFR mRNA in the 125I-bFGF mAb group was significantly decreased in comparison with other groups (P < 0.05). Groups under interventions revealed increased expression of VEGF mRNA (except for 125I group) compared with the control group.CONCLUSION: 125I-bFGF mAb inhibits growth of HCC xenografts. The coupling effect of 125I-bFGF mAb is more effective than the concomitant use of 125I and bFGF mAb.

乳腺癌受体阳转阴的发生机理与治疗进展

乳腺癌因其高度异质性,给乳腺癌精准治疗带来挑战。雌激素受体(estrogen receptor, ER)、孕激素受体(progesterone receptor, PR)和人表皮生长因子受体-2(human epidermal growth factor receptor-2, HER2)状态是乳腺癌精准诊疗的重要依据。对于复发或转移性乳腺癌患者,既往治疗主要基于原发病灶受体状态。但研究发现部分患者复发/转移灶受体表达与原发病灶不同,推测可能与肿瘤异质性和治疗后的克隆选择效应相关。相较于受体表达“阴转阳”,受体“阳转阴”的发生率更高,且受体表达的缺失可能导致对原有疗法耐药且预后不良。重新评估乳腺癌复发/转移灶受体状态对调整治疗策略和判断预后具有显著临床意义,但能否基于受体变化情况指导临床决策,在临床研究或实践层面仍存在较大争议。随着靶向药物、免疫疗法及抗体偶联药物(antibody-drug conjugates, ADC)等新型抗肿瘤药物的应用,如何优化受体“阳转阴”乳腺癌患者的治疗方案以提高疗效成为未解决的临床需求。该文旨在深入探讨乳腺癌受体“阳转阴”的机理、预后影响以及治疗现状,为这类患者的治疗提供理论支持和实践指导。

Emerging role of liquid biopsy in rat sarcoma virus mutated metastatic colorectal cancer:A case report

BACKGROUND In patients with metastatic colorectal cancer(mCRC),the treatment options are limited and have been proved to be affected by rat sarcoma virus(RAS)mutational status.In RAS wild-type(wt)patients,the combination of antiepidermal growth factor receptor(EGFR)monoclonal antibodies with chemotherapy(CT)is more effective than CT alone.On the other hand,RAS-mutated patients are not eligible for treatment with anti-EGFR antibodies.CASE SUMMARY Eleven patients with initially RAS-mutated mCRC were followed from diagnosis to May 2022.At the time of cell-free DNA determination,five patients had undergone one CT line,five patients had undergone two CT lines,and one patient had undergone three CT lines(all in combination with bevacizumab).At the second and third treatment lines[second line(2L),third line(3L)],patients with neo-RAS wt received a combination of CT and cetuximab.In neo-RAS wt patients treated with anti-EGFR,our findings indicated an increase in progression-free survival for both 2L and 3L(14.5 mo,P=0.119 and 3.9 mo,P=0.882,respectively).Regarding 2L overall survival,we registered a slight increase in neo-RAS wt patients treated with anti-EGFR(33.6 mo vs 32.4 mo,P=0.385).At data cut-off,two patients were still alive:A RAS-mutated patient undergoing 3L treatment and a neo-RAS wt patient who received 2L treatment with anti-EGFR(ongoing).CONCLUSION Our case series demonstrated that monitoring RAS mutations in mCRC by liquid biopsy may provide an additional treatment line for neo-RAS wt patients.

靶向HER2胞外结构域Ⅳ的单克隆抗体在乳腺癌中的应用进展

人表皮生长因子受体2(HER2)阳性乳腺癌侵袭性强且易转移,抗HER2靶向药物的应用能显著改善HER2阳性乳腺癌患者的预后。在已上市的HER2靶向药物中,靶向HER2胞外结构域Ⅳ的大分子单克隆抗体是治疗HER2阳性乳腺癌的基础靶向药物,主要包括曲妥珠单抗、伊尼妥单抗和马吉妥昔单抗。曲妥珠单抗用于乳腺癌全线治疗,循证医学证据充分,实践经验充足且安全性可控;伊尼妥单抗与曲妥珠单抗在HER2阳性转移性乳腺癌和新辅助/辅助治疗中疗效相似,且安全性可控;马吉妥昔单抗聚焦于携带CD16A-158F等位基因的患者,是晚期乳腺癌后线治疗的选择。临床上需根据患者具体病情选择最适合的药物。

抗体药物偶联物治疗非小细胞肺癌的研究进展和展望

抗体药物偶联物(ADC)代表一种新兴抗肿瘤治疗策略,融合了单克隆抗体的高度特异性和高细胞毒性药物的杀伤力。相对于传统化疗药物,ADC不仅能够精准识别肿瘤靶点,还能够实现药物快速传递到肿瘤细胞内,在降低全身毒副作用的同时提供更高的治疗效力。ADC已经在多种肿瘤类型中展现了出色的治疗效果,在非小细胞肺癌(NSCLC)中的应用也备受关注,本文就ADC在NSCLC治疗中的研究现状和前景进行综述。

抗体偶联药物在非小细胞肺癌中的研究进展

肺癌是全球发病率第一位、病死率第二位的恶性肿瘤。非小细胞肺癌(non-small cell lung cancer,NSCLC)是最主要的肺癌病理分型。目前晚期NSCLC的一线标准治疗方案为免疫治疗、靶向治疗,虽然延长了患者的生存期,但获得性耐药仍是不可避免的。抗体偶联药物(antibody-drug conjugates,ADCs)是一类经由连接子将细胞毒性载荷与特异性单克隆抗体偶联制成的新型抗肿瘤药物,与化疗药物相比,ADCs具有精准识别、局部释放、患者耐受性高等优点,近年在NSCLC治疗方面显示出良好的临床获益。本文针对ADCs的作用机制、在晚期NSCLC中的临床研究进展以及存在的问题和挑战等方面进行概述。

抗体药物偶联物治疗HER-2阳性乳腺癌的机制与研究进展

人表皮生长因子受体2(HER-2)阳性乳腺癌的诊治一直是乳腺癌领域的研究热点。单克隆抗体类药物和小分子酪氨酸激酶抑制剂的接连问世极大地改善了HER-2阳性乳腺癌患者的预后。然而,在极佳疗效的背后,靶向药物同样面临着多重耐药现象及心脏毒性等亟待解决的重大难题。近年来,随着HER-2阳性乳腺癌进入“精准分类,精确分层”的时代,抗体药物偶联物(ADC)成为肿瘤患者精准化治疗的热点领域之一。ADC通过特定的连接头将靶标特异性的单克隆抗体与高杀伤性的细胞毒性药物偶联起来,对肿瘤细胞具有高度特异性杀伤作用。本文就ADC的作用机制及其在HER-2阳性乳腺癌中的研究进展作一综述。

TCbHP在老年HER-2阳性乳腺癌患者新辅助化疗中的应用效果

目的:研究TCbHP在老年HER-2阳性乳腺癌患者新辅助化疗中的应用效果。方法:选取2020年3月—2022年4月苏州大学附属第三医院收治的100例老年HER-2阳性乳腺癌患者,随机将其分为对照组(n=50)和观察组(n=50)。对照组给予THP新辅助化疗,观察组给予TCbHP新辅助化疗。比较两组临床疗效、治疗前后肿瘤标志物及不良反应。结果:观察组客观缓解率高于对照组,差异有统计学意义(P<0.05)。治疗后,两组癌胚抗原与糖类抗原125水平均低于治疗前,观察组癌胚抗原与糖类抗原125水平均低于对照组,差异有统计学意义(P<0.05)。两组血小板减少、肝损伤、脱发、恶心呕吐、手足综合征发生率比较,差异无统计学意义(P>0.05)。结论:相比THP,TCbHP可进一步抑制老年HER-2阳性乳腺癌患者肿瘤标志物表达,有效控制疾病发展,不会加重化疗引起的不良反应。

Successful cetuximab rechallenge in metastatic colorectal cancer:A case report

BACKGROUND Metastatic colorectal cancer(mCRC)treatment has been evolving and increasingly driven by tumor biology and gene expression analysis.Rechallenge with epidermal growth factor receptor(EGFR)inhibitors(anti-EGFR)represents a promising strategy for patients with RAS wild-type(RAS-wt)mCRC and circulating tumor DNA has emerged as a potential selection strategy.Herein,we report the case of a RAS-wt mCRC patient who had a successful response to cetuximab rechallenge.CASE SUMMARY Our patient was diagnosed with stage IV RAS-wt,microsatellite-stable rectosigmoid junction adenocarcinoma.He was started on first-line treatment with FOLFIRI and cetuximab and achieved partial response,allowing for a left hepatectomy(R0),followed by post-operative chemotherapy and an anterior resection;progression-free survival(PFS)of 16 months was obtained.Due to hepatic and nodal relapse,second-line treatment with FOLFOX and bevacizumab was started with partial response;metastasectomy was performed(R0),achieving a PFS of 11 months.After a 15 months anti-EGFR-free interval,FOLFIRI and cetuximab were reintroduced upon disease progression,again with partial response and a PFS of 16 months.Following extensive hepatic relapse,cetuximab was reintroduced and a marked clinical and analytical improvement was seen,after only one cycle.RASwt status was confirmed on circulating tumor DNA.The patient’s overall survival exceeded 5 years.CONCLUSION Our case provides real-world data to support cetuximab rechallenge in later lines of RAS-wt mCRC treatment.

抗OX40/EGFR双特异性抗体的制备和活性鉴定

目的构建同时靶向表皮生长因子受体(epidermal growth factor receptor,EGFR)和OX40的双特异性抗体,并在体外初步验证其对T细胞的特异性激活作用。方法构建抗OX40/EGFR双特异性抗体的真核表达载体,转染293F细胞进行表达和纯化。构建外源表达OX40和EGFR的HEK293T细胞,利用流式细胞术分析双抗与靶蛋白表达细胞的结合活性。并利用Jurkat-OX40-NF-κB-GFP报告细胞,验证双特异性抗体对报告细胞的激活活性。通过酶联免疫吸附法(enzyme-linked immunosorbent assay,ELISA)检测外周血单个核细胞(peripheral blood mononuclear cell,PBMC)的白细胞介素-2(interleukin-2,IL-2)和γ-干扰素(interferon-γ,IFN-γ)分泌,进一步验证抗OX40/EGFR双抗对原代T细胞的激活。结果成功构建并且纯化了抗OX40/EGFR双特异性抗体,并且验证了该双抗可以特异性地结合表达EGFR和OX40的HEK293T细胞。在表达EGFR的A549肺癌细胞介导的交联作用下,该双特异性抗体较OX40单抗更强地激活OX40-NF-κB报告细胞,并且促进PBMC分泌IL-2和IFN-γ细胞因子。结论抗OX40/EGFR双特异性抗体构建成功,可同时识别OX40和EGFR受体并激活肿瘤特异性T细胞。

抗体药物偶联物在人表皮生长因子受体2低表达胃癌中的应用研究进展

胃癌(GC)是极具异质性和侵袭性的消化系统恶性肿瘤之一,传统化疗药物及曲妥珠单抗等人表皮生长因子受体2(HER2)靶向药物在GC的治疗过程中仍然存在耐药性发生率高、毒副作用大、患者耐受差等缺点。因此,研发更为有效的抗GC药物势在必行。目前针对HER2的新型靶向药层出不穷,但在某些情况下无效或产生耐药,这与HER2在某些GC细胞中低表达有关,HER2低表达(HER2 IHC1+或IHC2+/ISH-)约占全部类型的40%~60%,但在临床实践中,这类患者仍被报告为HER2阴性GC。因此准确检测HER2表达状态对于确定可能受益于曲妥珠单抗治疗的患者至关重要。抗体药物偶联物(ADC)的出现为HER2阳性GC提供了新的治疗选择,凭借其精准高效的抗肿瘤作用,有望在未来替代传统GC化学疗法。近期有研究发现ADC可能在HER2低表达GC中具有潜在抗肿瘤活性,相关临床研究正在评估其在HER2低表达GC治疗中的有效性和安全性。本文就靶向治疗时代ADC在HER2低表达GC患者中的应用和最新研究进展作一综述,并讨论HER2靶向ADC在应用和研发过程中面临的挑战。