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      The use of radiocobalt as a label improves imaging of EGFR using DOTA-conjugated Affibody molecule

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          Abstract

          Several anti-cancer therapies target the epidermal growth factor receptor (EGFR). Radionuclide imaging of EGFR expression in tumours may aid in selection of optimal cancer therapy. The 111In-labelled DOTA-conjugated Z EGFR:2377 Affibody molecule was successfully used for imaging of EGFR-expressing xenografts in mice. An optimal combination of radionuclide, chelator and targeting protein may further improve the contrast of radionuclide imaging. The aim of this study was to evaluate the targeting properties of radiocobalt-labelled DOTA-Z EGFR:2377. DOTA-Z EGFR:2377 was labelled with 57Co (T 1/2 = 271.8 d), 55Co (T 1/2 = 17.5 h), and, for comparison, with the positron-emitting radionuclide 68Ga (T 1/2 = 67.6 min) with preserved specificity of binding to EGFR-expressing A431 cells. The long-lived cobalt radioisotope 57Co was used in animal studies. Both 57Co-DOTA-Z EGFR:2377 and 68Ga-DOTA-Z EGFR:2377 demonstrated EGFR-specific accumulation in A431 xenografts and EGFR-expressing tissues in mice. Tumour-to-organ ratios for the radiocobalt-labelled DOTA-Z EGFR:2377 were significantly higher than for the gallium-labelled counterpart already at 3 h after injection. Importantly, 57Co-DOTA-Z EGFR:2377 demonstrated a tumour-to-liver ratio of 3, which is 7-fold higher than the tumour-to-liver ratio for 68Ga-DOTA-Z EGFR:2377. The results of this study suggest that the positron-emitting cobalt isotope 55Co would be an optimal label for DOTA-Z EGFR:2377 and further development should concentrate on this radionuclide as a label.

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          Epidermal growth factor receptor gene and protein and gefitinib sensitivity in non-small-cell lung cancer.

          Gefitinib is a selective inhibitor of the epidermal growth factor (EGFR) tyrosine kinase, which is overexpressed in many cancers, including non-small-cell lung cancer (NSCLC). We carried out a clinical study to compare the relationship between EGFR gene copy number, EGFR protein expression, EGFR mutations, and Akt activation status as predictive markers for gefitinib therapy in advanced NSCLC. Tumors from 102 NSCLC patients treated daily with 250 mg of gefitinib were evaluated for EGFR status by fluorescence in situ hybridization (FISH), DNA sequencing, and immunohistochemistry and for Akt activation status (phospho-Akt [P-Akt]) by immunohistochemistry. Time to progression, overall survival, and 95% confidence intervals (CIs) were calculated and evaluated by the Kaplan-Meier method; groups were compared using the log-rank test. Risk factors associated with survival were evaluated using Cox proportional hazards regression modeling and multivariable analysis. All statistical tests were two-sided. Amplification or high polysomy of the EGFR gene (seen in 33 of 102 patients) and high protein expression (seen in 58 of 98 patients) were statistically significantly associated with better response (36% versus 3%, mean difference = 34%, 95% CI = 16.6 to 50.3; P<.001), disease control rate (67% versus 26%, mean difference = 40.6%, 95% CI = 21.5 to 59.7; P<.001), time to progression (9.0 versus 2.5 months, mean difference = 6.5 months, 95% CI = 2.8 to 10.3; P<.001), and survival (18.7 versus 7.0 months, mean difference = 11.7 months, 95% CI = 2.1 to 21.4; P = .03). EGFR mutations (seen in 15 of 89 patients) were also statistically significantly related to response and time to progression, but the association with survival was not statistically significant, and 40% of the patients with mutation had progressive disease. In multivariable analysis, only high EGFR gene copy number remained statistically significantly associated with better survival (hazard ratio = 0.44, 95% CI = 0.23 to 0.82). Independent of EGFR assessment method, EGFR+/P-Akt+ patients had a statistically significantly better outcome than EGFR-, P-Akt-, or EGFR+/P-Akt- patients. High EGFR gene copy number identified by FISH may be an effective molecular predictor for gefitinib efficacy in advanced NSCLC.
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            Feedback regulation of EGFR signalling: decision making by early and delayed loops.

            Human-made information relay systems invariably incorporate central regulatory components, which are mirrored in biological systems by dense feedback and feedforward loops. This type of system control is exemplified by positive and negative feedback loops (for example, receptor endocytosis and dephosphorylation) that enable growth factors and receptor Tyr kinases of the epidermal growth factor receptor (EGFR)/ERBB family to regulate cellular function. Recent studies show that the collection of feedback regulatory loops can perform computational tasks - such as decoding ligand specificity, transforming graded input signals into a digital output and regulating response kinetics. Aberrant signal processing and feedback regulation can lead to defects associated with pathologies such as cancer.
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              Impact of epidermal growth factor receptor expression on survival and pattern of relapse in patients with advanced head and neck carcinoma.

              A correlative study was performed to address the impact of epidermal growth factor receptor (EGFR) overexpression on survival and pattern of failure in patients with advanced head and neck squamous cell carcinomas (HNSCCs) enrolled in a Phase III trial and randomized to receive conventional radiotherapy. The study population comprised 155 of 268 (58%) randomized patients with sufficient pretreatment biopsy specimens for immunohistochemical assay. The specimens were dewaxed and incubated after standard preparation with mouse monoclonal antibodies recognizing the extracellular domain of the EGFR molecule. The catalyzed product was visualized with 3,3'-diaminobenzidine Chromogen Kit and lightly counterstained with Mayer's hematoxylin. Quantitative EGFR immunohistochemistry (IHC) was done with SAMBA 4000 Cell Image Analysis System, without knowledge of the clinical outcome, to yield mean absorbance (MOD), staining index (SI), and quick score (QS). These EGFR IHC parameters were correlated with the T stage, N stage, combined stage grouping, and recursive partitioning analysis classes. Subsequently, the EGFR parameters were correlated with the outcome end points, i.e., overall survival (OS), disease-free survival (DFS), local-regional (LR) relapse, and distant metastasis rates. We found that HNSCCs exhibited a wide variation in EGFR expression (MOD, 0.2-66.0; SI, 0.3-97.0; QS, 0.01-69.9) with a relatively strong but nonlinear correlation between MOD and SI (r = 0.79). There was no correlation between EGFR expression and T stage, N stage, stage grouping, and recursive partitioning analysis classes (r = -0.07 to 0.17). The OS and DFS rates of patients with high EGFR-expressing HNSCCs (>median MOD) were highly significantly lower (P = 0.0006 and P = 0.0016, respectively) and the LR relapse rate was highly significantly higher (P = 0.0031) compared with those of patients with low EGFR-expressing HNSCCs. However, there was no difference in the distant metastasis rate between the two groups (P = 0.96). Significant correlations, although somewhat less robust than MOD, were also observed between SI and QS and the OS, DFS, and LR relapse rates. Multivariate analysis showed that EGFR expression was an independent determinant of survival and a robust independent predictor of LR relapse. In summary, this correlative study in a large series of patients revealed that EGFR expression, which varied considerably among HNSCCs, was a strong independent prognostic indicator for OS and DFS and a robust predictor for LR relapse but not for distant metastasis. The data suggest that EGFR IHC should be considered for selecting patients for more aggressive combined therapies or enrollment into trials targeting EGFR signaling pathways.
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                Author and article information

                Contributors
                vladimir.tolmachev@igp.uu.se
                Journal
                Sci Rep
                Sci Rep
                Scientific Reports
                Nature Publishing Group UK (London )
                2045-2322
                20 July 2017
                20 July 2017
                2017
                : 7
                : 5961
                Affiliations
                [1 ]ISNI 0000 0004 1936 9457, GRID grid.8993.b, Department of Immunology, Genetics and Pathology, , Uppsala University, ; Uppsala, Sweden
                [2 ]ISNI 0000000121581746, GRID grid.5037.1, Department of Protein Technology, , KTH - Royal Institute of Technology, ; Stockholm, Sweden
                [3 ]ISNI 0000 0004 0512 5013, GRID grid.7143.1, Department of Nuclear Medicine, , Odense University Hospital, ; Sdr. Boulevard 29, 5000 Odense, Denmark
                [4 ]ISNI 0000 0004 1936 9457, GRID grid.8993.b, Division of Molecular Imaging, Department of Medicinal Chemistry, , Uppsala University, ; Uppsala, Sweden
                Author information
                http://orcid.org/0000-0001-6577-7011
                http://orcid.org/0000-0003-3955-1320
                Article
                5700
                10.1038/s41598-017-05700-7
                5519605
                d74ae750-3d5e-472a-8a67-0246a2530dd4
                © The Author(s) 2017

                Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

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                : 20 December 2016
                : 1 June 2017
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