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1.
Gliomas are the most common primary central nervous system tumours and about 55% are glioblastoma multiforme (GBM). Between 40% and 50% of GBM have dysregulated epidermal growth factor receptor (HER1/EGFR), and almost half of these co-express the mutant receptor subtype EGFRvIII, which may contribute to the aggressive and refractory course of GBM. Limited therapeutic options exist for GBM, and recurrence is common. Standard therapy is surgical resection, where possible, and radiotherapy. Adjuvant chemotherapy provides a modest survival benefit. New therapies are essential, and HER1/EGFR-targeted agents may provide a viable strategy. The HER1/EGFR tyrosine kinase inhibitors erlotinib and gefitinib are in advanced clinical development for glioma, and a number of trials are in progress, or have recently been completed. Preliminary results with gefitinib show no objective responses, but do provide evidence of disease control. In contrast, preliminary data with erlotinib appear more encouraging. Erlotinib inhibits wild-type HER1/EGFR and EGFRvIII, which may underlie its promising clinical activity. Other HER1/EGFR-targeted agents are also being investigated for glioma, including monoclonal antibodies, radio-immuno conjugates, ligand-toxin conjugates, antisense oligonucleotides and ribozymes. Further studies will define their clinical potential and hopefully provide new, effective treatments for GBM and other malignant brain tumours.  相似文献   

2.
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.  相似文献   

3.
目的 分析放疗联合表皮生长因子受体(EGFR)单抗治疗局部晚期头颈部鳞癌(LA-SCCHN)疗效。方法 2009—2011年间 77例SCCHN接受了调强放疗为主联合西妥昔单抗或尼妥珠单抗的患者入研究组,依性别、年龄、病种、分期、放疗技术与研究组一致原则选取同时期放疗未联合EGFR抑制剂的 72例LA-SCCHN患者作为对照组。比较两组局部控制率、生存率及急性不良反应并分析预后影响因素。Kaplan-Meier计算局部控制率、生存率并Logrank法检验,Cox模型多因素预后分析。结果 研究组、对照组中位随访时间分别为18.0、19.5个月,随访率100%。2年局部控制率、总生存率、无瘤生存率分别为78%和60%(χ2=4.88,P=0.027)、64%和59%(χ2=0.87,P=0.351)、60%和46%(χ2=2.12,P=0.146)。研究组较对照组患者3+4级放射性黏膜炎高(51%∶17%,χ2=19.09,P=0.000)、白细胞下降发生率也高(8%∶0%,χ2=4.00,P=0.045)。多因素预后分析显示原发部位、T分期、N分期、是否同期化疗、是否联合EGFR单抗是局部控制的影响因素。结论 与放疗未联合EGFR抑制剂相比调强放疗联合EGFR单抗治疗LA-SCCHN提高了局部控制率,但未提高总生存率和无瘤生存率,且不良反应可耐受。  相似文献   

4.
Monoclonal antibodies against the epidermal growth factor receptor have proven efficacy as monotherapy and in combination with chemotherapy in patients with metastatic colorectal cancer (CRC: mCRC). Initial clinical trials in CRC used the human-murine chimeric monoclonal antibody cetuximab. Ongoing studies are being conducted to evaluate the efficacy and safety of the fully human anti-epiderman growth factor receptor monoclonal antibody panitumumab. The results of a phase III trial which compared panitumumab as a single agent to best supportive care in patients with previously treated metastatic CRC have recently been reported Pantitumumab therapy resulted in a 46% reduction in the risk of tumor progression and a partial response rate of 8%. Rash was reported in 90% of patients with increased severity significantly correlated with improved medium overall survival (OS). Further clinical studies re ongoing and planned to test panitumumab in combination with chemotherapy in first-line therapy of advanced-stage CRC and adjuvant treatment of colon cancer.  相似文献   

5.
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Epidermal growth factor receptor (EGFR) has been an attractive target for treatment of epithelial cancers, including colorectal cancer (CRC). Evidence from clinical trials indicates that cetuximab and panitumumab (anti-EGFR monoclonal antibodies) have clinical activity in patients with metastatic CRC. The discovery of intrinsic EGFR blockade resistance in Kirsten RAS (KRAS)-mutant patients led to the restriction of anti-EGFR antibodies to KRAS wild-type patients by Food and Drug Administration and European Medicine Agency. Studies have since focused on the evaluation of biomarkers to identify appropriate patient populations that may benefit from EGFR blockade. Accumulating evidence suggests that patients with mutations in EGFR downstream signaling pathways including KRAS, BRAF, PIK3CA and PTEN could be intrinsically resistant to EGFR blockade. Recent whole genome studies also suggest that dynamic alterations in signaling pathways downstream of EGFR leads to distinct oncogenic signatures and subclones which might have some impact on emerging resistance in KRAS wild-type patients. While anti-EGFR monoclonal antibodies have a clear potential in the management of a subset of patients with metastatic CRC, further studies are warranted to uncover exact mechanisms related to acquired resistance to EGFR blockade.  相似文献   

7.

Background

We previously identified platelet-activating factor receptor (PAFR) as being overexpressed in ovarian cancer and found that its ligand PAF evoked EGFR phosphorylation using the phospho-antibody microarray. Epidermal growth factor receptor (EGFR) are also overexpressed in ovarian cancer and contribute to the growth of ovarian cancer cells. Here, we investigated the mechanisms of crosstalk between PAFR and EGFR signaling in ovarian cancer cells to further determine whether the interaction between PAFR and EGFR synergistic contribute to the progression of ovarian cancer.

Methods

Expression and localization of PAFR in several ovarian cancer cell lines were assessed by Western blot, realtime-PCR and immunofluorescence. The ovarian cancer cells were stimulated with PAF or PAF and in some experiments also pharmacological inhibitors. Phosphorylation of proteins in signaling pathways were measured by Western blot. HB-EGF concentrations of the supernatant from stimulated ovarian cancer cells were measured by enzyme-linked immunosorbent assay.

Results

Our data show that PAF increases EGFR phosphorylation through PAFR in a time- and dose- dependent manner in SKOV-3 ovarian cancer cells. This transactivation is dependent on phospholipase C-β and intracellular calcium signaling. This pathway is also Src tyrosine kinase- and metalloproteinase- dependent. PAF triggers EGFR activation through the increased heparin-binding EGF-like growth factor (HB-EGF) release in metalloprotease-dependent manner. Several studies involving EGFR transactivation through G-protein coupled receptor (GPCR) have demonstrated EGFR-dependent increase in ERK1/2 phosphorylation. Yet in SKOV-3 cells, PAF treatment also increases ERK1/2 phosphorylation in a EGFR-independent manner.

Conclusions

The results suggest that in SKOV-3 ovarian cancer cells, PAF transactivates EGFR and downstream ERK pathways, thus diversifying the GPCR-mediated signal. The crosstalk between PAFR and EGFR suggests a potentially important signaling linkage between inflammatory and growth factor signaling in ovarian cancer cells.  相似文献   

8.
Epidermal growth factor receptors (EGFR) are overexpressed in a wide range of malignancies including head and neck, colon, and breast cancers. It has been identified that carcinomas with high expression levels of EGFR are more resistant to radiotherapy. Therefore, inhibiting nuclear translocation of EGFR to increase the radiosensitivity of malignant cells expressing EGFR offers the potential for increasing the therapeutic index of radiotherapy. The purpose of the present study was to quantify and to compare the radiosensitizing properties of the well-known anti-EGFR antibodies, cetuximab and nimotuzumab in human epidermoid A431 overexpressing EGFR cells. Cells were treated with two concentrations of the antibodies and then irradiated with a single dose of 4 Gy. The results indicated that the two antibodies induced radiosensitization increasing the percentage of dead/dying cells and the yield of γ-H2AX foci 24 h after irradiation. Whereas cetuximab exhibited a significant increase in radiosensitization at the highest concentration, the effects of nimotuzumab were more modest. A correlation between γ-H2AX foci signals and dead/dying cells was observed. The disparity in modulation of radiation-induced DNA damage by the two antibodies could be associated with the level of their respective intrinsic cytotoxic properties. Overall, the findings highlight the potential therapeutic benefit of combination therapy with anti-EGFR antibodies and radiotherapy for relevant carcinomas.  相似文献   

9.
Epidermal growth factor receptor (EGFR) signaling plays an important role in cell growth and differentiation. Mutations in the EGFR gene and EGFR gene amplifications have been associated with increased responsiveness to selective EGFR tyrosine kinase inhibitors (EGFR-TKIs). By contrast, EGF may also stimulate apoptosis in tumor cells, depending on EGFR and Her2 (erbB-2) expression levels. In the present study, we investigated cellular responses after EGFR activation by EGF, or inhibition by cetuximab and gefitinib. EGF treatment induced a near-immediate increase in p38 MAPK phosphorylation together with inactivation of ERK1/2. In contrast, gefitinib- and cetuximab-induced phosphorylation of p38 MAPK was much delayed, and gefitinib also induced a delayed activation of ERK1/2. EGF induced progressive cell death of A431 cells with prolonged treatment, whereas cetuximab- or gefitinib-treated cells showed temporary growth arrest and subsequent re-growth. Moreover, in combination treatment experiments, cetuximab or gefitinib competitively inhibited EGF-induced cell death. Normal WI38-VA13 cells did not display any noticeable changes in cell proliferation in response to EGF, gefitinib or cetuximab. EGF-induced death signaling is apparently irreversible: EGF induced significant EGFR phosphorylation/internalization and activated caspase-3, -8 and -9, effects that were not observed in cetuximab- or gefitinib-treated cells. Collectively, these results indicate that EGF may be a more potent cytotoxic agent than EGFR blockers in EGFR-overexpressing cancer cells.  相似文献   

10.
BackgroundApproximately 50% of newly diagnosed glioblastomas (GBMs) harbor epidermal growth factor receptor gene amplification (EGFR-amp). Preclinical and early-phase clinical data suggested efficacy of depatuxizumab mafodotin (depatux-m), an antibody–drug conjugate comprised of a monoclonal antibody that binds activated EGFR (overexpressed wild-type and EGFRvIII-mutant) linked to a microtubule-inhibitor toxin in EGFR-amp GBMs.MethodsIn this phase III trial, adults with centrally confirmed, EGFR-amp newly diagnosed GBM were randomized 1:1 to radiotherapy, temozolomide, and depatux-m/placebo. Corneal epitheliopathy was treated with a combination of protocol-specified prophylactic and supportive measures. There was 85% power to detect a hazard ratio (HR) ≤0.75 for overall survival (OS) at a 2.5% 1-sided significance level (ie traditional two-sided p ≤ 0.05) by log-rank testing.ResultsThere were 639 randomized patients (median age 60, range 22–84; 62% men). Prespecified interim analysis found no improvement in OS for depatux-m over placebo (median 18.9 vs. 18.7 months, HR 1.02, 95% CI 0.82–1.26, 1-sided p = 0.63). Progression-free survival was longer for depatux-m than placebo (median 8.0 vs. 6.3 months; HR 0.84, 95% confidence interval [CI] 0.70–1.01, p = 0.029), particularly among those with EGFRvIII-mutant (median 8.3 vs. 5.9 months, HR 0.72, 95% CI 0.56–0.93, 1-sided p = 0.002) or MGMT unmethylated (HR 0.77, 95% CI 0.61–0.97; 1-sided p = 0.012) tumors but without an OS improvement. Corneal epitheliopathy occurred in 94% of depatux-m-treated patients (61% grade 3–4), causing 12% to discontinue.ConclusionsInterim analysis demonstrated no OS benefit for depatux-m in treating EGFR-amp newly diagnosed GBM. No new important safety risks were identified.  相似文献   

11.
Photoimmunotherapy (PIT) is a new cancer treatment that combines the specificity of antibodies for targeting tumors with the toxicity induced by photosensitizers after exposure to near infrared (NIR) light. Herein we compare two commonly available anti‐EGFR monoclonal antibodies, cetuximab and panitumumab, for their effectiveness as PIT agents in EGFR positive tumor models. A photosensitizer, IR‐700, conjugated to either cetuximab (cet‐IR700) or panitumumab (pan‐IR700), was evaluated using EGFR‐expressing A431 and MDAMB468‐luc cells in 2D‐ and 3D‐culture. PIT was conducted with irradiation of NIR light after exposure of the sample or animal to each conjugate. In vivo PIT was performed with fractionated exposure of NIR light after injection of each agent into A431 xenografts or a MDAMB468‐luc orthotopic tumor bearing model.Cet‐IR700 and pan‐IR700 bound with equal affinity to the cells in 2D‐culture and penetrated equally into the 3D‐spheroid, resulting in identical PIT cytotoxic effects in vitro. In contrast, in vivo anti‐tumor effects of PIT with cet‐IR700 were inferior to that of pan‐IR700. Assessment of the biodistribution showed lower accumulation into the tumors and more rapid hepatic catabolism of cet‐IR700 compared to pan‐IR700. Although cet‐IR700 and pan‐IR700 showed identical in vitro characteristics, pan‐IR700 showed better therapeutic tumor responses than cet‐IR700 in in vivo mice models due to the prolonged retention of the conjugate in the circulation, suggesting that retention in the circulation is advantageous for tumor responses to PIT. These results suggest that the choice of monoclonal antibody in photosensitizer conjugates may influence the effectiveness of PIT.  相似文献   

12.
The mouse monoclonal antibody (mAb) 225 IgG1 against the epidermal growth factor (EGF) receptor has been investigated for its capacity to localize in human tumor xenografts. The EGF receptor is the product of the c-erb-B proto-oncogene (also known as EGFR). Elevated expression of EGF receptors has been demonstrated in many human tumors and tumor cell lines. We studied A431 human vulvar squamous cell carcinoma cells, with 2 X 10(6) receptors per cell; MDA-MB-468 (MDA 468) human breast adenocarcinoma cells, with 3 X 10(5) receptors per cell; and MCF-7 human breast adenocarcinoma cells, with 5 X 10(3) receptors per cell. The 111In-labeled pentetic acid (DTPA), derivative of mAb 225 (111In-DTPA-225) was injected intraperitoneally into nude mice bearing subcutaneous tumor xenografts. We measured uptake by quantifying radioactivity in tumor and normal tissues and by obtaining gamma camera images. Uptake in A431 xenografts was 28% +/- 2.4% of the injected dose per gram of tumor on day 3 and 12.4% +/- 3.0% on day 7. Distribution ratios comparing uptake in the tumor with that in normal tissues were consistently greater than 4. In contrast, there was far less uptake of the control mAb KS1/4S-1 labeled with 111In. This conjugate, 111In-DTPA-KS1/4S-1, has an IgG1 isotype but does not bind to human or murine cells. Imaging of the tumor with mAb 225 was excellent, especially on days 3-7. MDA 468 xenografts exhibited reduced localization of mAb 225 in the tumor. For MCF-7 xenografts, the tumor uptake of mAb 225 after 7 days was only 0.70% +/- 0.10% of the injected dose per gram of tumor, which was comparable to the uptake of the KS1/4S-1 control mAb. The ratio of the concentration of radioactivity in the tumor to that in normal tissue (distribution ratio) showed poor selectivity of uptake, and imaging was not obtained. These observations suggest that labeled mAb can target the product of a proto-oncogene, the EGF receptor, when it is expressed at high levels in human tumor xenografts.  相似文献   

13.
近年来,随着对肿瘤形成机制的进一步了解以及分子生物学的进展,针对肿瘤形成发展过程中异常生物学途径的靶向治疗日益发展起来,研究表明靶向药物能够抑制肿瘤生长的活性,而且与放疗或化疗具有协同作用.但放化综合治疗会产生较大的毒副反应,从而限制了其在肿瘤治疗中的应用.靶向治疗的出现,使得放射治疗和靶向治疗联合应用于恶性肿瘤的新策略成为可能.表皮生长因子受体(Epidermal growth factor receptor,EGFR)是目前研究最多、应用最广的靶向药物治疗靶点,本文就目前肿瘤治疗中针对EGFR的靶向药物与放射治疗联合应用的机制、其与放射敏感性的关系做一综述.  相似文献   

14.
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16.
Epidermal growth factor (EGF)-related proteins such as transforming growth factor alpha (TGF-alpha) control cancer cell growth through autocrine and paracrine pathways. Overexpression of TGF-alpha and/or its receptor (EGFR) has been associated with a more aggressive disease and a poor prognosis. The blockade of EGFR activation has been proposed as a target for anticancer therapy. Monoclonal antibody (MAb) C225 is an anti-EGFR humanized chimeric mouse MAb that is presently in Phase II clinical trials in cancer patients. Previous studies have suggested the potentiation of the antitumor activity of certain cytotoxic drugs, such as cisplatin and doxorubicin, in human cancer cell lines by treatment with anti-EGFR antibodies. We have evaluated in human ovarian, breast, and colon cancer cell lines, which express functional EGFR, the antiproliferative activity of MAb C225 in combination with topotecan, a cytotoxic drug that specifically inhibits topoisomerase I and that has shown antitumor activity in these malignancies. A dose-dependent supraadditive increase of growth inhibition in vitro was observed when cancer cells were treated with topotecan and MAb C225 in a sequential schedule. In this respect, the cooperativity quotient, defined as the ratio between the actual growth inhibition obtained by treatment with topotecan followed by MAb C225 and the sum of the growth inhibition achieved by each agent, ranged from 1.2 to 3, depending on drug concentration and cancer cell line. Treatment with MAb C225 also markedly enhanced apoptotic cell death induced by topotecan. For example, in GEO colon cancer cells, 5 nM topotecan, followed by 0.5 microg/ml MAb C225, induced apoptosis in 45% cells as compared with untreated cells (6%) or to 5 nM topotecan-treated cells (22%). Treatment of mice bearing established human GEO colon cancer xenografts with topotecan or with MAb C225 determined a transient inhibition of tumor growth because GEO tumors resumed the growth rate of untreated tumors at the end of the treatment period. In contrast, an almost complete tumor regression was observed in all mice treated with the two agents in combination. This determined a prolonged life span of the mice that was significantly different as compared with controls (P < 0.001), to MAb C225-treated group (P < 0.001), or to the topotecan-treated group (P < 0.001). All mice of the topotecan plus MAb C225 group were the only animals alive 14 weeks after tumor cell injection. Furthermore, 20% of mice in this group were still alive after 19 weeks. The combined treatment with MAb C225 and topotecan was well tolerated by mice with no signs of acute or delayed toxicity. These results provide a rationale for the evaluation of the anticancer activity of the combination of topoisomerase I inhibitors and anti-EGFR blocking MAbs in clinical trials.  相似文献   

17.
Interaction of insulin-like growth factor receptor I (IGF-IR) with its ligands has been reported to induce cell proliferation, transformation and blockade of cell apoptotic functions. IGF-IR is overexpressed on numerous tumor cell types and its blockade could be of importance for anti-cancer therapy. We have generated a humanized anti-IGF-IR antibody h7C10 that blocks in vitro IGF-I and IGF-II-induced cell proliferation of MCF-7 breast cancer cells. Analysis of the IGF-I transduction cascade demonstrated that the humanized anti-IGF-IR antibody and its murine parental form block IGF-I-induced tyrosine phosphorylation, both its beta-chain and IRS-1 tyrosine phosphorylation. This presumably leads to cell cycle arrest and, consequently, growth inhibition. Treatment of nude mice bearing either human breast cancer cells (MCF-7) or non small lung cancer cells (A549) with h7C10, or its murine parental form 7C10, inhibited significantly tumor growth. An almost complete inhibition of A549 tumor growth was observed when mice were treated with the anti-IGF-IR antibody combined with either a chemotherapeutic agent, Vinorelbine or an anti-epidermal growth factor receptor (EGFR) antibody, 225. Combined therapy prolonged significantly the life span of mice in an orthotopic in vivo model of A549; the combination of the anti-IGF-IR antibody with an anti-EGFR antibody was superior to the Vinorelbine combination. The present results indicate that the humanized anti-IGF-IR antibody h7C10 has a great potential for cancer therapy when combined with either a chemotherapeutic agent or an antibody that targets other growth factor receptors, such as the epidermal growth factor receptor.  相似文献   

18.
The recent successful development of monoclonal antibodies that target key components of biological pathways has expanded the armamentarium of treatment options for patients with colorectal cancer (CRC). In particular, the epidermal growth factor receptor (EGFR), a tyrosine kinase growth factor receptor involved in CRC development and progression, is exploited by the newest monoclonal antibody that is available for use in CRC patients. Cetuximab, the first chimeric monoclonal antibody, which has been generated against the EGFR, is currently registered in USA, Europe and worldwide, in combination with irinotecan in the treatment of metastatic CRC patients who have progressed on irinotecan containing chemotherapy. Cetuximab is well tolerated and does not exacerbate the toxicity of concomitant chemotherapy. Furthermore, a series of phase III clinical trials are currently evaluating the combination of cetuximab with standard chemotherapy regimens in the first-line treatment chemotherapy-na?ve patients with metastatic CRC.  相似文献   

19.
Yuan TZ  Li XX  Cao Y  Qian CN  Zeng MS  Guo X 《癌症》2008,27(5):449-454
背景与目的:表皮生长因子受体(epidermal growth factor receptor,EGFR)在多种肿瘤中高表达,且与预后相关,然而,EGFR对鼻咽癌的预后价值尚存争议。本研究检测鼻咽癌组织中EGFR及其磷酸化形式(phosphorylated EGFR,pEGFR)的表达,探讨其与鼻咽癌预后的关系。方法:收集中山大学肿瘤防治中心1999年1月至12月住院治疗鼻咽癌患者的鼻咽癌组织110例,同时收集20例正常鼻咽组织。利用免疫组化方法检测鼻咽癌组织及正常鼻咽组织中EGFR及pEGFR的表达,半定量方法评价染色情况;采用单因素和多因素方法分析蛋白表达与临床病理特征及预后的关系。结果:EGFR及pEGFR在鼻咽癌组织和鼻咽正常组织的阳性率分别为100%(110/110)、10%(2/20)和60%(66/110)、15%(3/20),不同组织中两种蛋白表达的差异均具有统计学意义(P<0.001);EGFR蛋白高表达与T分期相关(P=0.034),而与其他临床病理特征无关。单因素分析显示pEGFR高表达患者5年无转移生存率显著低于pEGFR低表达患者(72.2%vs.91.0%,P=0.012),而多因素分析显示pEGFR表达不是鼻咽癌患者无转移生存的独立预后因素。结论:pEGFR高表达与鼻咽癌患者的无转移生存相关,EGFR活化可能与鼻咽癌的转移有关。  相似文献   

20.
背景与目的生活质量是评价非小细胞肺癌治疗方法的重要指标。本研究的目的是观察表皮生长因子受体抑制剂gefitinib对晚期非小细胞肺癌患者生活质量的影响。方法对gefitinib慈善用药计划中31例晚期非小细胞肺癌患者进行研究。患者每日口服gefitinib250mg,直至病情进展或出现严重的副反应。采用中文版EORTCQLQ-C30和QLQ-LC13问卷对治疗前后症状和生活质量的改变进行评价。结果25例接受gefitinib治疗的患者完成问卷。和治疗前相比,治疗8周后,患者4种功能状态(体格、角色、情感、社会)和整体生活质量评分的均值显著增加,全身症状(乏力和食欲不振)以及疾病相关症状(呼吸困难、咳嗽、胸痛、手臂和肩膀疼痛、身体其他部位疼痛)评分的均值显著降低。治疗后5种功能状态和整体生活质量的有效率均超过50%。主要的全身症状和疾病相关症状的有效率也达到44%~84%。症状和生活质量的改善与临床客观疗效相一致。结论gefitinib对于常规治疗失败的晚期非小细胞肺癌仍能够改善患者的症状和生活质量。  相似文献   

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