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Shaw JA, Page K, Wren E, de Bruin EC, Kalashnikova E, Hastings R, McEwen R, Zhang E, Wadsley M, Acheampong E, Renner D, Gleason KLT, Ambasager B, Stetson D, Fernandez-Garcia D, Guttery D, Allsopp RC, Rodriguez A, Zimmermann B, Sethi H, Aleshin A, Liu MC, Richards C, Stebbing J, Ali S, Rehman F, Cleator S, Kenny L, Ahmed S, Armstrong AC, Coombes RC. Serial Postoperative Circulating Tumor DNA Assessment Has Strong Prognostic Value During Long-Term Follow-Up in Patients With Breast Cancer. JCO Precis Oncol 2024; 8:e2300456. [PMID: 38691816 DOI: 10.1200/po.23.00456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 12/09/2023] [Accepted: 01/18/2024] [Indexed: 05/03/2024] Open
Abstract
PURPOSE Here, we report the sensitivity of a personalized, tumor-informed circulating tumor DNA (ctDNA) assay (Signatera) for detection of molecular relapse during long-term follow-up of patients with breast cancer. METHODS A total of 156 patients with primary breast cancer were monitored clinically for up to 12 years after surgery and adjuvant chemotherapy. Semiannual blood samples were prospectively collected, and analyzed retrospectively to detect residual disease by ultradeep sequencing using ctDNA assays, developed from primary tumor whole-exome sequencing data. RESULTS Personalized Signatera assays detected ctDNA ahead of clinical or radiologic relapse in 30 of the 34 patients who relapsed (patient-level sensitivity of 88.2%). Relapse was predicted with a lead interval of up to 38 months (median, 10.5 months; range, 0-38 months), and ctDNA positivity was associated with shorter relapse-free survival (P < .0001) and overall survival (P < .0001). All relapsing triple-negative patients (n = 7/23) had a ctDNA-positive test within a median of 8 months (range, 0-19 months), while the 16 nonrelapsed patients with triple-negative breast cancer remained ctDNA-negative during a median follow-up of 58 months (range, 8-99 months). The four patients who had negative tests before relapse all had hormone receptor-positive (HR+) disease and conversely, five of the 122 nonrelapsed patients (all HR+) had an occasional positive test. CONCLUSION Serial postoperative ctDNA assessment has strong prognostic value, provides a potential window for earlier therapeutic intervention, and may enable more effective monitoring than current clinical tests such as cancer antigen 15-3. Our study provides evidence that those with serially negative ctDNA tests have superior clinical outcomes, providing reassurance to patients with breast cancer. For select cases with HR+ disease, decisions about treatment management might require serial monitoring despite the ctDNA-positive result.
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Affiliation(s)
- Jacqueline A Shaw
- Leicester Cancer Research Centre, University of Leicester, Leicester, United Kingdom
| | - Karen Page
- Leicester Cancer Research Centre, University of Leicester, Leicester, United Kingdom
| | - Evie Wren
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Elza C de Bruin
- Oncology R&D, Research & Early Development, AstraZeneca, Cambridge, United Kingdom
| | | | - Robert Hastings
- Leicester Cancer Research Centre, University of Leicester, Leicester, United Kingdom
| | - Rob McEwen
- Oncology R&D, Research & Early Development, AstraZeneca, Cambridge, United Kingdom
| | - Eddie Zhang
- Oncology R&D, Research & Early Development, AstraZeneca, Waltham, MA
| | - Marc Wadsley
- Leicester Cancer Research Centre, University of Leicester, Leicester, United Kingdom
| | - Emmanuel Acheampong
- Leicester Cancer Research Centre, University of Leicester, Leicester, United Kingdom
| | | | - Kelly L T Gleason
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Bana Ambasager
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Daniel Stetson
- Oncology R&D, Research & Early Development, AstraZeneca, Waltham, MA
| | | | - David Guttery
- Leicester Cancer Research Centre, University of Leicester, Leicester, United Kingdom
| | - Rebecca C Allsopp
- Leicester Cancer Research Centre, University of Leicester, Leicester, United Kingdom
| | | | | | | | | | | | - Cathy Richards
- University Hospitals Leicester NHS Trust, Leicester, United Kingdom
| | - Justin Stebbing
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Simak Ali
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Farah Rehman
- Imperial College Healthcare NHS Trust, London, United Kingdom
| | - Susan Cleator
- Imperial College Healthcare NHS Trust, London, United Kingdom
| | - Laura Kenny
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Samreen Ahmed
- University Hospitals Leicester NHS Trust, Leicester, United Kingdom
| | - Anne C Armstrong
- Division of Cancer Sciences, The Christie NHS Foundation Trust, Manchester, United Kingdom
| | - R Charles Coombes
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
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Martinez Saez O, Felip Falgas E, Cappelletti M, Tolosa P, Brasó-Maristany F, Sanfeliu Torres E, Pascual T, Chic N, Vidal M, Adamo B, Munoz M, Faull I, Odegaard J, Patel G, McEwen R, Carroll D, Ciruelos E, Generali D, Margeli Vila M, Prat A. 10P Survival according to early ctDNA dynamics in advanced breast cancer (ABC) treated with endocrine therapy (ET) and a CDK4/6 inhibitor (CDK4/6i). Ann Oncol 2022. [DOI: 10.1016/j.annonc.2022.03.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Hrebien S, Citi V, Garcia-Murillas I, Cutts R, Fenwick K, Kozarewa I, McEwen R, Ratnayake J, Maudsley R, Carr TH, de Bruin EC, Schiavon G, Oliveira M, Turner N. Early ctDNA dynamics as a surrogate for progression-free survival in advanced breast cancer in the BEECH trial. Ann Oncol 2020; 30:945-952. [PMID: 30860573 PMCID: PMC6594458 DOI: 10.1093/annonc/mdz085] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Background Dynamic changes in circulating tumour DNA (ctDNA) levels may predict long-term outcome. We utilised samples from a phase I/II randomised trial (BEECH) to assess ctDNA dynamics as a surrogate for progression-free survival (PFS) and early predictor of drug efficacy. Patients and methods Patients with estrogen receptor-positive advanced metastatic breast cancer (ER+ mBC) in the BEECH study, paclitaxel plus placebo versus paclitaxel plus AKT inhibitor capivasertib, had plasma samples collected for ctDNA analysis at baseline and at multiple time points in the development cohort (safety run-in, part A) and validation cohort (randomised, part B). Baseline sample ctDNA sequencing identified mutations for longitudinal analysis and mutation-specific digital droplet PCR (ddPCR) assays were utilised to assess change in ctDNA abundance (allele fraction) between baseline and 872 on-treatment samples. Primary objective was to assess whether early suppression of ctDNA, based on pre-defined criteria from the development cohort, independently predicted outcome in the validation cohort. Results In the development cohort, suppression of ctDNA was apparent after 8 days of treatment (P = 0.014), with cycle 2 day 1 (4 weeks) identified as the optimal time point to predict PFS from early ctDNA dynamics. In the validation cohort, median PFS was 11.1 months in patients with suppressed ctDNA at 4 weeks and 6.4 months in patients with high ctDNA (hazard ratio = 0.20, 95% confidence interval 0.083–0.50, P < 0.0001). There was no difference in the level of ctDNA suppression between patients randomised to capivasertib or placebo overall (P = 0.904) nor in the PIK3CA mutant subpopulation (P = 0.071). Clonal haematopoiesis of indeterminate potential (CHIP) was evident in 30% (18/59) baseline samples, although CHIP had no effect on tolerance of chemotherapy nor on PFS. Conclusion Early on-treatment ctDNA dynamics are a surrogate for PFS. Dynamic ctDNA assessment has the potential to substantially enhance early drug development. Clinical registration number NCT01625286.
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Affiliation(s)
- S Hrebien
- Breast Cancer Now Research Centre, The Institute of Cancer Research, London, UK
| | - V Citi
- Breast Cancer Now Research Centre, The Institute of Cancer Research, London, UK; Clinical Pharmacology and Pharmacogenetics Unit, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - I Garcia-Murillas
- Breast Cancer Now Research Centre, The Institute of Cancer Research, London, UK
| | - R Cutts
- Breast Cancer Now Research Centre, The Institute of Cancer Research, London, UK
| | - K Fenwick
- Breast Cancer Now Research Centre, The Institute of Cancer Research, London, UK
| | - I Kozarewa
- Oncology, IMED Biotech Unit, AstraZeneca, Cambridge, UK
| | - R McEwen
- Oncology, IMED Biotech Unit, AstraZeneca, Cambridge, UK
| | - J Ratnayake
- Oncology, IMED Biotech Unit, AstraZeneca, Cambridge, UK
| | - R Maudsley
- Oncology, IMED Biotech Unit, AstraZeneca, Cambridge, UK
| | - T H Carr
- Oncology, IMED Biotech Unit, AstraZeneca, Cambridge, UK
| | - E C de Bruin
- Oncology, IMED Biotech Unit, AstraZeneca, Cambridge, UK
| | - G Schiavon
- Oncology, IMED Biotech Unit, AstraZeneca, Cambridge, UK
| | - M Oliveira
- Vall d'Hebron University Hospital and Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
| | - N Turner
- Breast Cancer Now Research Centre, The Institute of Cancer Research, London, UK; Breast Unit, Royal Marsden Hospital, London, UK.
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Carroll D, McEwen R, Kozarewa I, Harrington E, L'Hernault A, Ratnayake J, Mather R, Hodgson D, Barrett JC, Cosaert JGCE, Brachet PE, Grivas P, Chowdhury S, Powles T, Landers D. Correlation of circulating tumor DNA (ctDNA), tissue-based genomic profiling and clinical efficacy in the biomarker directed Ph1b trial in metastatic bladder cancer (BISCAY). J Clin Oncol 2019. [DOI: 10.1200/jco.2019.37.15_suppl.4553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
4553 Background: BISCAY is a biomarker-directed Ph1b multi-arm platform study exploring the combination of targeted therapies with anti-PD-L1, Durvalumab, in advanced urothelial cancer. Methods: Next generation sequencing (NGS) of tumour tissue samples from > 380 patients(pts) was performed using the FoundationOne assay alongside IHC for PD-L1. ct DNA from pts enrolled in trial modules at treatment initiation was profiled using the Guardant Health OMNI platform assessing a panel of 500 genes. For a subset of pts, serial plasma samples were also analysed to monitor early signs of response vs. resistance and changes in ct DNA dynamics using a bespoke NGS panel of 10 genes. Results: To date 149 pts have been actively enrolled across 7 different biomarker selected and unselected treatment modules. Across all screened pts the most prevalent genomic alterations in tumour tissue were TERT promoter (65%), TP53 (59%), KMT2D 21%, KDM6A 21%, with the most common CNV CDKN2A/ B loss (32 %). All enrolled pts tested had detectable ctDNA in plasma. Similar genomic alterations, both frequency and type, were detected in both plasma ctDNA and tumour tissue with high concordance for module specific biomarkers used for patient allocation (80% (8/10) for ATM, BRCA1 and 2). Alterations in putative biomarkers predictive of response to anti-PD-L1, such as HRR/MMR alterations and high bTMB levels ( > 20mut/Mb) were observed in22% and 40% patient plasma samples, respectively. Correlations between biomarkers across modules treatment efficacy have been explored. Conclusions: All pts with advanced bladder cancer enrolled on BISCAY who were plasma profiled had detectable ctDNA; frequencies of genomic alterations (in both tumour tissue and plasma) were comparable to prior published data sets. ctDNA may be an attractive alternative to tissue-based NGS, providing comprehensive dynamic snapshots of genomic landscapes at the start and during therapy, and warrants further prospective investigation in trials.
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Affiliation(s)
- Danielle Carroll
- Translational Science, Oncology, IMED Biotech Unit, AstraZeneca, Cambridge, United Kingdom
| | | | - Iwanka Kozarewa
- Translational Science, Oncology, IMED Biotech Unit, AstraZeneca, Cambridge, United Kingdom
| | - Elizabeth Harrington
- Oncology Translational Science, IMED Biotech Unit, AstraZeneca, Cambridge, United Kingdom
| | | | | | | | | | - J Carl Barrett
- Translational Sciences, IMED Biotech Unit, AstraZeneca, Waltham, MA
| | | | | | - Petros Grivas
- University of Washington, School of Medicine, Seattle, WA
| | - Simon Chowdhury
- Guy’s, King’s and St. Thomas’ Hospitals, and Sarah Cannon Research Institute, London, United Kingdom
| | - Thomas Powles
- Barts Cancer Institute, Queen Mary University of London, Royal Free NHS Trust, London, United Kingdom
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Oelmann E, Michaloglou C, Crafter C, Siersbaek R, Delpuech O, Curven J, Carnevalli L, Staniszweska A, Polanska U, Cheraghchi-Bashi A, Lawson M, Chernukhin I, McEwen R, Carroll J, Cosulich S. Abstract PD4-04: Combined inhibition of mTOR and CDK4/6 is required for optimal blockade of E2F function and long term growth inhibition in estrogen receptor positive breast cancer. Cancer Res 2018. [DOI: 10.1158/1538-7445.sabcs17-pd4-04] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
The cyclin dependent kinase (CDK) –retinoblastoma (RB) -E2F pathway plays a critical role in the control of cell cycle in estrogen receptor positive (ER+) breast cancer. Small molecule inhibitors of CDK4/6 have shown promise in this tumour type in combination with hormonal therapies, reflecting the particular dependence of this subtype of cancer on cyclin D1 and E2F transcription factors. mTOR inhibitors have also shown potential in clinical trials in this disease setting. Recent data has suggested cooperation between the phosphatidylinositol 3-kinase (PI3K) pathway and CDK4/6 inhibition in preventing early adaptation and eliciting growth arrest, but the mechanisms of the interplay between these pathways have not been fully elucidated. Here we show that profound and durable inhibition of ER+ breast cancer growth is likely to require multiple hits on E2F mediated transcription. We demonstrate that inhibition of mTOR using the mTORC1/2 inhibitor vistusertib at 300nM causes a >50% decrease in cyclin D1 protein levels and RB phosphorylation in three cell lines. At these concentrations, vistusertib treatment also elicits marked effects on E2F mediated transcription, causing changes in the mRNA levels of 28 out of 43 (65%) of a selected set of E2F target genes.Combined inhibition of mTOR, CDK4/6 and ER delivers profound and durable regressions in breast cancer cell lines and xenografts (110.2% tumour growth inhibition at day 48). In vivo data show, that over a period of 58 days, tumours failed to re-grow in the presence of the triplet combination compared to either agent alone, suggesting, that the triplet is necessary to maintain growth inhibition. Furthermore, we show that CDK4/6 inhibitor resistant cell lines re-activate the CDK-RB-E2F pathway, but remain sensitive to mTOR inhibition (EC50 52.7 nM in parental cells vs 39.6-73.3 nM in a number of palbociclib resistant cell populations), suggesting that mTORC1/2 inhibitors may represent an option for patients that have relapsed on CDK4/6 therapy. A Phase I study (PASTOR) combining the dual TOR kinase inhibitor Vistusertib with Palbociclib, and Fulvestrant is underway to explore safety and efficacy of the triplet combination in patients with metastatic breast cancer.
Citation Format: Oelmann E, Michaloglou C, Crafter C, Siersbaek R, Delpuech O, Curven J, Carnevalli L, Staniszweska A, Polanska U, Cheraghchi-Bashi A, Lawson M, Chernukhin I, McEwen R, Carroll J, Cosulich S. Combined inhibition of mTOR and CDK4/6 is required for optimal blockade of E2F function and long term growth inhibition in estrogen receptor positive breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD4-04.
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Affiliation(s)
- E Oelmann
- AstraZeneca, Cambridge, Cambridgeshire, United Kingdom; CRUK Cambridge Institute, Cambridge, Cambridgeshire, United Kingdom; University of Bradford, Bradford, Cheshire, United Kingdom
| | - C Michaloglou
- AstraZeneca, Cambridge, Cambridgeshire, United Kingdom; CRUK Cambridge Institute, Cambridge, Cambridgeshire, United Kingdom; University of Bradford, Bradford, Cheshire, United Kingdom
| | - C Crafter
- AstraZeneca, Cambridge, Cambridgeshire, United Kingdom; CRUK Cambridge Institute, Cambridge, Cambridgeshire, United Kingdom; University of Bradford, Bradford, Cheshire, United Kingdom
| | - R Siersbaek
- AstraZeneca, Cambridge, Cambridgeshire, United Kingdom; CRUK Cambridge Institute, Cambridge, Cambridgeshire, United Kingdom; University of Bradford, Bradford, Cheshire, United Kingdom
| | - O Delpuech
- AstraZeneca, Cambridge, Cambridgeshire, United Kingdom; CRUK Cambridge Institute, Cambridge, Cambridgeshire, United Kingdom; University of Bradford, Bradford, Cheshire, United Kingdom
| | - J Curven
- AstraZeneca, Cambridge, Cambridgeshire, United Kingdom; CRUK Cambridge Institute, Cambridge, Cambridgeshire, United Kingdom; University of Bradford, Bradford, Cheshire, United Kingdom
| | - L Carnevalli
- AstraZeneca, Cambridge, Cambridgeshire, United Kingdom; CRUK Cambridge Institute, Cambridge, Cambridgeshire, United Kingdom; University of Bradford, Bradford, Cheshire, United Kingdom
| | - A Staniszweska
- AstraZeneca, Cambridge, Cambridgeshire, United Kingdom; CRUK Cambridge Institute, Cambridge, Cambridgeshire, United Kingdom; University of Bradford, Bradford, Cheshire, United Kingdom
| | - U Polanska
- AstraZeneca, Cambridge, Cambridgeshire, United Kingdom; CRUK Cambridge Institute, Cambridge, Cambridgeshire, United Kingdom; University of Bradford, Bradford, Cheshire, United Kingdom
| | - A Cheraghchi-Bashi
- AstraZeneca, Cambridge, Cambridgeshire, United Kingdom; CRUK Cambridge Institute, Cambridge, Cambridgeshire, United Kingdom; University of Bradford, Bradford, Cheshire, United Kingdom
| | - M Lawson
- AstraZeneca, Cambridge, Cambridgeshire, United Kingdom; CRUK Cambridge Institute, Cambridge, Cambridgeshire, United Kingdom; University of Bradford, Bradford, Cheshire, United Kingdom
| | - I Chernukhin
- AstraZeneca, Cambridge, Cambridgeshire, United Kingdom; CRUK Cambridge Institute, Cambridge, Cambridgeshire, United Kingdom; University of Bradford, Bradford, Cheshire, United Kingdom
| | - R McEwen
- AstraZeneca, Cambridge, Cambridgeshire, United Kingdom; CRUK Cambridge Institute, Cambridge, Cambridgeshire, United Kingdom; University of Bradford, Bradford, Cheshire, United Kingdom
| | - J Carroll
- AstraZeneca, Cambridge, Cambridgeshire, United Kingdom; CRUK Cambridge Institute, Cambridge, Cambridgeshire, United Kingdom; University of Bradford, Bradford, Cheshire, United Kingdom
| | - S Cosulich
- AstraZeneca, Cambridge, Cambridgeshire, United Kingdom; CRUK Cambridge Institute, Cambridge, Cambridgeshire, United Kingdom; University of Bradford, Bradford, Cheshire, United Kingdom
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Fleischmann R, van Vollenhoven RF, Smolen J, Emery P, Florentinus S, Rathmann S, Kupper H, Kavanaugh A, Taylor P, Genovese M, Keystone EC, Drescher E, Berclaz PY, Lee C, Fidelus-Gort R, Schlichting D, Beattie S, Luchi M, Macias W, Kavanaugh A, Emery P, van Vollenhoven RF, Dikranian AH, Alten R, Klearman M, Musselman D, Agarwal S, Green J, Gabay C, Weinblatt ME, Schiff MH, Fleischmann R, Valente R, van der Heijde D, Citera G, Zhao C, Maldonado MA, Rakieh C, Nam JL, Hunt L, Villeneuve E, Bissell LA, Das S, Conaghan P, McGonagle D, Wakefield RJ, Emery P, Wright HL, Thomas HB, Moots R, Edwards SW, Hamann P, Heward J, McHugh N, Lindsay MA, Haroon M, Giles JT, Winchester R, FitzGerald O, Karaderi T, Cohen CJ, Keidel S, Appleton LH, Macfarlane GJ, Siebert S, Evans D, Paul Wordsworth B, Plant D, Bowes J, Orozco G, Morgan AW, Wilson AG, Isaacs J, Barton A, Williams FM, Livshits G, Spector T, MacGregor A, Williams FM, Scollen S, Cao D, Memari Y, Hyde CL, Zhang B, Sidders B, Ziemek D, Shi Y, Harris J, Harrow I, Dougherty B, Malarstig A, McEwen R, Stephens JL, Patel K, Shin SY, Surdulescu G, He W, Jin X, McMahon SB, Soranzo N, John S, Wang J, Spector TD, Baker J, Litherland GJ, Rowan AD, Kite KA, Bayley R, Yang P, Smith JP, Williams J, Harper L, Kitas GD, Buckley C, Young SP, Fitzpatrick MA, Young SP, McGettrick HM, Filer A, Raza K, Nash G, Buckley C, Muthana M, Davies H, Khetan S, Adeleke G, Hawtree S, Tazzyman S, Morrow F, Ciani B, Wilson G, Quirke AM, Lugli E, Wegner N, Charles P, Hamilton B, Chowdhury M, Ytterberg J, Potempa J, Fisher B, Thiele G, Mikuls T, Venables P, Adebajo AO, Kavanaugh A, Mease P, Gomez-Reino JJ, Wollenhaupt J, Hu C, Stevens R, Sieper J, van der Heijde D, Dougados M, Van den Bosch F, Goupille P, Rathmann SS, Pangan AL, van der Heijde D, Sieper J, Maksymowych WP, Brown MA, Rathmann S, Pangan AL, Sieper J, van der Heijde D, Elewaut D, Pangan AL, Anderson J, Haroon M, Ramasamy P, O'Rourke M, Murphy C, Fitzgerald O, Jani M, Moore S, Mirjafari H, Macphie E, Chinoy H, Rao C, McLoughlin Y, Preeti S. Oral Abstracts 7: RA Clinical * O37. Long-Term Outcomes of Early RA Patients Initiated with Adalimumab Plus Methotrexate Compared with Methotrexate Alone Following a Targeted Treatment Approach. Rheumatology (Oxford) 2013. [DOI: 10.1093/rheumatology/ket198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Rosli N, McGoldrick C, McEwen R, Laing R, Mackenzie A, Douglas J. Bacteraemias in injecting drug users – the Grampian experience. J Infect 2007. [DOI: 10.1016/j.jinf.2007.04.096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Talmadge JE, Talmadge CB, Zbar B, McEwen R, Meeker AK, Tribble H. In vivo immunologic selection of class I major histocompatibility complex gene deletion variants from the B16-BL6 melanoma. J Natl Cancer Inst 1987; 78:1215-21. [PMID: 3473258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The mechanism by which tumor allografts escape host immunologic attack was investigated. B16-BL6 cells (the bladder 6 subline of the B16 melanoma) (H-2b) were transfected with a gene (Dd) encoding an allogeneic class I major histocompatibility complex antigen. Clones that expressed Dd antigen were injected into the footpads of nonimmune syngeneic mice, syngeneic immune mice, and nude mice. Under conditions of immunologic selection a clone that contained multiple copies of the transfected gene formed variants that lacked the transfected gene. Primary tumors and pulmonary metastases of immunized mice and pulmonary metastases of nonimmunized mice had lost the Dd gene and, in most cases, all of the associated plasmid. In contrast, in immunodeficient nude mice, primary tumors and pulmonary metastases retained the Dd gene and the associated plasmid. Deletion of genes encoding cell surface antigens may be one of the mechanisms by which allogeneic tumors escape immunologic attack.
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