- Email: [email protected]
EP-1820: RAD17 and DNA replication as a potential target for improving radiotherapy in prostate cancer
S296 models of radiation-induced lung fibrosis (RILF) are a way to evaluate new treatment strategies, but until recently their clinical utility was limited due to non-relevant radiation dose distributions. Dedicated precision image-guided small animal irradiator devices are now available that better mimic clinical radiotherapy making them well suited to study and quantify RILF. In this study we quantified local changes in lung density after partial lung irradiation in mice using micro-CT imaging. Materials and Methods: C57BL/6 adult male mice (n=75) were divided into six groups and treated with a single fraction of irradiation of 0, 4, 8, 12, 16 or 20 Gy. Mice were irradiated with 5-mm circular parallelopposed fields targeting the upper right lung using a dedicated small animal irradiator (P225Cx, PXInc, CT, USA) sparing the heart and spine. Micro-CT images were acquired at 200 µm3 resolution. A Monte Carlo model of the small animal irradiation was used for dose calculations. Regions-of-interests(ROIs) were created for the left (non-irradiated) and right lung, the dose region, and the union of the right lung and the high dose (>20% max dose) region. Following irradiation, all mice were imaged every four weeks for a total of 39 weeks (i.e. 10 time points). Non-rigid deformation was used to deform all ROIs from the initial microCT scan to all sequential scans. The mean Hounsfield Unit (HU) from each ROI from each animal group was extracted and evaluated. Results: Increased lung density, consistent with the development of fibrotic tissue, could be visually observed by CT in the late stage imaging time points of irradiated mice after 20 Gy confirming that RILF could be induced in partial lung irradiation. RILF was spatially limited to the irradiated portion of the lung. Significant differences in the change in HU between the 0 and 20 Gy were observed as early as the 10th week postirradiation. By the time of the last imaging session significant differences could be observed between the three highest (>10 Gy) and three lowest irradiation (<10 Gy) dose levels. A mean difference of 110 ± 10 HU between the 0 and 20 Gy groups was observed at week 39.
ESTRO 33, 2014
ELECTRONIC POSTER: RADIOBIOLOGY PREDICTIVE ASSAYS/PROGNOSTIC FACTORS
TRACK:
EP-1819 REQUITE: Validating predictive models and biomarkers of RT toxicity to reduce side-effects and improve QOL D. De Ruysscher1, C. Talbot2, D. Azria3, J. Chang-Claude4, A. Dunning5, S. Gutiérrez Enríquez6, A. Vega7, L. Lozza8, L. Veldeman9, C.M. West10 1 University Hospital Gasthuisberg/ KU Leuven, Radiation Oncology, Leuven, Belgium 2 University of Leicester, Radiation Oncology, Leicester, United Kingdom 3 University of Montpellier, Radiation Oncology, Montpellier, France 4 German Cancer Research Centre (DKFZ), Epidemiology, Heidelberg, Germany 5 University of Cambridge, Genetic Epidemiology, Cambridge, United Kingdom 6 University of Barcelona, Vall d’Hebron Institute of Oncology-VHIO, Barcelona, Spain 7 Fundación Pública Galega Medicina Xenómica, Fundación Pública Galega Medicina Xenómica, Santiago de Compostela, Spain 8 Fondazione IRCCS Istituto Nazionale dei Tumori, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy 9 University of Ghent, Radiation Oncology, Ghent, Belgium 10 University of Manchester, Radiation Oncology, Manchester, United Kingdom Purpose/Objective: Recently the first replicated genetic associations for adverse reactions to radiotherapy were reported. These should improve predictive statistical models for optimising radiotherapy delivery or interventions to alleviate the side effects. It is now timely to start a project that aims to validate known predictors of adverse reactions and develop the statistical models to become clinically useful. The REQUITE project is a European Union funded FP7 project that aims to do this. REQUITE’s objectives: 1. Perform a multi-centre, cohort study collecting: blood samples, epidemiology and treatment data, longitudinal sideeffect and QOL data (before and after treatment, years 1 & 2). 2. Produce a centralised database and biobank of DNA for 5,300 patients. 3. Validate published biomarkers of radiosensitivity. 4. Validate clinical predictors of radiotherapy toxicity in breast, prostate and lung cancer and incorporate biomarker data. 5. Design interventional trials to reduce long-term side-effects. 6. Provide a resource for dissemination and exploitation to the radiotherapy community. Materials and Methods: The central activity of the project is a multicentre, observational study organised through WP2.Enrolment will proceed for 2 years in nine clinical centres, with 2 years follow-up. The primary endpoints are change in breast appearance; rectal bleeding (prostate); pneumonitis (lung). The integrated database will be designed. Blood samples will be collected before radiotherapy. Tracking, biobanking and DNA extraction is handled in WP3. Validation of biomarkers (genetic markers and apoptosis assays) as predictive factors will be carried out in WP4. Some clinical factors have suggested predictive value for radiotherapy side-effects, but there is no consensus. In WP5 these will be validated in existing cohorts. In WP6, predictive models will be used to design clinical interventional trials and produce protocols that seek to lower radiotherapy side-effects in those individuals at high risk of developing them without affecting tumour control. Results: As the project has started in October 2013, no results are available yet. Conclusions: No conclusions can be formulated yet.
Fig.(TOP) Axial and coronal CT slices of the dose region (A,C) and the region outside the dose region but limited to the same lung (B,D). (BOTTOM) The changein HUs between the two regions in the lung Conclusions: The use of high precision treatment in combination with non-invasive micro-CT imaging was found to be a useful quantitative tool in monitoring changes in HU due to RILF.We have shown that partial volume irradiation, more similar to patient irradiation than conventionally used whole body/organ irradiation, induces RILFin mice and can be used to evaluate new treatment strategies.
EP-1820 RAD17 and DNA replication as a potential target for improving radiotherapy in prostate cancer C. Gani1, L. Basler1, D. Ostafichuk2, G. Zafarana2, R.G. Bristow2 1 Eberhard Karls-University Tübingen, Radiation Oncology, Tübingen, Germany 2 Princess Margaret Cancer Centre, Radiation Medicine Program, Toronto, Canada Purpose/Objective: Prostate cancer is the most common non-skin malignancy in men and radiotherapy is a curative modality for clinically localized (but non-indolent) disease. Despite increased precision of
ESTRO 33, 2014 treatment, up to 30% of men with intermediate-risk disease fail radiotherapy due to either localized or systemic resistance. We hypothesized that the status of DNA replication genes may relate to inter-patient radiotherapy response and be a target to improve radiotherapy outcome. Materials and Methods: Using in-house array-CGH on DNA derived from radiotherapy patients’ tumours coupled with in silico RNA expression analyses, we have noted abnormal expression of DNA replication and repair proteins in 10-20% of patients with intermediate risk disease. RAD17 is a master protein involved in the recruitment of the RAD9-RAD1HUS1 (9-1-1) complex to chromatin and activatesthe CHK1 kinase during an S-phase replication cell-cycle checkpoint. To test the functional significance of this clinical genomic finding, we generated a Doxycyclineinducible shRNAi system in 22RV1 prostate cancer cells and analyzed the impact of RAD17 expression on DNA replication and cell proliferation, radiation clonogenic survival and DNA repair foci. Results: We observed a mono-allelic loss of RAD17 in 10% ofpatients which supports studies that test whether lowering levels of RAD17 might sensitize tumours to radiotherapy. By titrating Doxycycline doses we were able to induce a knockdown of RAD17 expression to 50% and 0% relative to the wild-type level. Cells deficient in RAD17 exhibit a significantly decreased growth rate by slowing of S-phase progression. Clonogenic survival assays showed increased sensitivity to ionizing radiation after a knockdown of RAD17 associated with an increased number of residual DNA-DSB repair foci (gamma H2AX and 53BP1). Conclusions: Prostate cancers may have DNA replication abnormalities that could be targeted to reduce prostate cancer radioresistance. These results have implications for the prediction of individualized radiotherapy response and the targeting of abnormal DNA replication as a clinical radiosensitization strategy. (Funded by the Ontario Institute for Cancer Research, the Terry Fox Research Institute, the Canadian Cancer Society and the German Cancer Aid). EP-1821 Prognostic and predictive value of serial plasma Osteopontin levels in the radiotherapy of NSCLC C. Ostheimer1, M. Bache1, A. Güttler1, D. Vordermark1 1 Martin Luther University Halle-Wittenberg, Radiation Oncology, Halle / Saale, Germany Purpose/Objective: Overexpression and elevated plasma levels of the hypoxia-related protein osteopontin (OPN) appear to be a strong prognostic indicator in many malignancies. We recently demonstrated that a co-detection of the hypoxia-related proteins OPN, CA9 and VEGF is more robust in predicting prognosis in the curative-intended radiotherapy for advanced NSCLC than a single plasma marker (Ostheimer et al., Strahlenther Onkol in press). In this prospective clinical study we evaluated the prognostic and predictive value of serial plasma OPN in the curative-intended radiotherapy for NSCLC. Materials and Methods: 69 patients with inoperable NSCLC were prospectively included into the study (55 in M0 and 14 in M1 stage). OPN plasma levels were measured before (t0), at the end (t1) and four weeks after radiotherapy (t2) by enzyme-linked-immuno-sorbent-assay and were correlated with clinicopathological parameters in the entire collective (n=69). The prognostic and predictive power of serial plasma OPN was evaluated in curative-intent (M0) patients who underwent definitive 66-Gy radiotherapy ± chemotherapy. Results: Pre-treatment OPN levels were associated with T-stage (p=.03), lung function (p= .002), weight loss (p=.01), tumor volume (GTV, p=.02) and hemoglobin concentration (p=.04) in the entire patient cohort. M1stage patients had significantly elevated OPN plasma levels at all measurement timepoints compared to M0 patients (p<.0001). Median OPN levels non-significantly decreased from before to after radiotherapy and OPN levels during and after radiotherapy trended to be associated with initial tumor control. Patients with increasing OPN levels after radiotherapy had a significantly reduced freedom-from-relapse (p=.008), overall survival (p=.004) and event-free survival (p=.001) compared to patients with stable or decreasing post-treatment OPN plasma levels. The risk for relapse in patients with increasing or stable OPN levels after radiotherapy was significantly higher compared to patients with decreasing OPN levels after treatment (rr=2.9, p=.01). Increasing posttreatment OPN levels translated into a 3.1-fold increased risk for death as opposed to stable or decreasing OPN plasma levels after treatment (p=.002). Post-treatment OPN plasma levels remained an independent prognostic factor for overall survival (p=.002) in an exploratory multivariate model.
S297 Conclusions: Our results indicate that not absolute but rather OPN level changes over time, particularly in the post-treatment timeframe, may yield additional prognostic and predictive information in the curativeintended radiotherapy for NSCLC. EP-1822 The Radiogenomics Consortium (RGC) C.M.L. West8, B.S. Rosenstein2, S.M. Bentzen3, G.C. Barnett4, A. Dunning5, S.L. Kerns2, J. Chang-Claude6, J.O. Deasy7, C.N. Andreassen1 1 Aarhus University Hospital, Dept. of Experimental Clinical Oncology, Aarhus C, Denmark 2 Mount Sinai Hospital, Icahn School of Medicine, New York, USA 3 University of Maryland, Division of Biostatistics and Bioinformatics, Baltimore, USA 4 Addenbrooke's Hospital, Department of Oncology, Cambridge, United Kingdom 5 Cambridge University, Centre for Cancer Genetic Epidemiology, Cambridge, United Kingdom 6 German Cancer Research Center (DKFZ), Division of Cancer Epidemiology, Heidelberg, Germany 7 Memorial Sloan-Kettering Cancer Centre, Memorial Hospital Research Laboratories, New York, USA 8 University of Manchester, Institute of Cancer Sciences, Manchester, United Kingdom Purpose/Objective: The Radiogenomics Consortium (RGC) was established in 2009. It has approximately 150 members from more than 80 institutions in 19 countries. The purpose of the consortium is to expand the knowledge of the genetic basis for differences in radiosensitivity. The RGC undertakes collaborative projects to identify SNPs associated with adverse effects of radiotherapy, share data and samples, perform meta-analyses, and work together to submit research grant applications. Several collaborative projects have been published. A meta-analysis addressing the impact of the TGFB1 position -509 (rs1800469) SNP upon risk of radiation induced fibrosis after radiotherapy for breast cancer. This study included 2782 patients from 11 different cohorts. Though the study was powered to detect a very small difference in normal tissue complication risk, no association was identified for this SNP (Barnett et al Radiother Oncol 2012). A replicated association between polymorphisms near TNFα and risk of adverse reactions to radiotherapy (Talbot et al. Br J Cancer 2012). A set of reporting guidelines for radiogenomics research have been published (Kerns et al. Radiother Oncol 2013). Other projects are ongoing. A meta-analysis of the impact of the ATM codon 1853 (rs1801516) SNP upon risk of radiation induced toxicity after radiotherapy for breast and prostate cancer. This study included 5434 patients and the preliminary results indicate a small but significant effect of this SNP upon risk of various normal tissue reactions. A metaanalysis of data from four genome wide association studies (RAPPER, RADIOGEN, Gene-PARE, Cross Cancer Institute) addressing toxicity after radiotherapy for prostate cancer (n=1,614) has identified a locus on chr11q22 that is associated with daytime urinary frequency. A multicentre study is attempting to validate previously reported SNP associations in breast cancer patients. The RGC recently obtained 6 million Euros of funding for the REQUITE project from the European Commission's FP7 program. REQUITE aims to prospectively collect clinical data and biological specimens in an observational study of 5300 patients with prostate, breast or lung cancer in order to establish and validate predictive models for normal tissue radiosensitivity. Collaboration has been established with the GameOn OncoArray project that addresses cancer susceptibility and plans to genotype 400,000 cancer patients using a custom made 5000K SNP array. This collaboration offers the RGC the opportunity to do GWAS studies and assess selected SNPs at a very affordable cost. Furthermore, the RGC may have the opportunity to access outcome data from those patients that received radiotherapy. The RGC is open to all investigators interested in studying the relationship between genetic variation and radiation therapy toxicity. To join email [email protected]. EP-1823 Proteome-based identification of biomarkers to predict radiation resistance in cancer patients S. Skvortsov1, P. Eichberger1, I. Skvortsova1, P. Lukas1 1 Innsbruck Medical University, Dept. of Therapeutic Radiology and Oncology, Innsbruck, Austria Purpose/Objective: Radiation therapy plays an important role in the management of malignant tumors, however the problem of radiation resistance resulting in tumor local or distant recurrences after treatment
ESTRO 33, 2014
ELECTRONIC POSTER: RADIOBIOLOGY PREDICTIVE ASSAYS/PROGNOSTIC FACTORS
TRACK:
EP-1819 REQUITE: Validating predictive models and biomarkers of RT toxicity to reduce side-effects and improve QOL D. De Ruysscher1, C. Talbot2, D. Azria3, J. Chang-Claude4, A. Dunning5, S. Gutiérrez Enríquez6, A. Vega7, L. Lozza8, L. Veldeman9, C.M. West10 1 University Hospital Gasthuisberg/ KU Leuven, Radiation Oncology, Leuven, Belgium 2 University of Leicester, Radiation Oncology, Leicester, United Kingdom 3 University of Montpellier, Radiation Oncology, Montpellier, France 4 German Cancer Research Centre (DKFZ), Epidemiology, Heidelberg, Germany 5 University of Cambridge, Genetic Epidemiology, Cambridge, United Kingdom 6 University of Barcelona, Vall d’Hebron Institute of Oncology-VHIO, Barcelona, Spain 7 Fundación Pública Galega Medicina Xenómica, Fundación Pública Galega Medicina Xenómica, Santiago de Compostela, Spain 8 Fondazione IRCCS Istituto Nazionale dei Tumori, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy 9 University of Ghent, Radiation Oncology, Ghent, Belgium 10 University of Manchester, Radiation Oncology, Manchester, United Kingdom Purpose/Objective: Recently the first replicated genetic associations for adverse reactions to radiotherapy were reported. These should improve predictive statistical models for optimising radiotherapy delivery or interventions to alleviate the side effects. It is now timely to start a project that aims to validate known predictors of adverse reactions and develop the statistical models to become clinically useful. The REQUITE project is a European Union funded FP7 project that aims to do this. REQUITE’s objectives: 1. Perform a multi-centre, cohort study collecting: blood samples, epidemiology and treatment data, longitudinal sideeffect and QOL data (before and after treatment, years 1 & 2). 2. Produce a centralised database and biobank of DNA for 5,300 patients. 3. Validate published biomarkers of radiosensitivity. 4. Validate clinical predictors of radiotherapy toxicity in breast, prostate and lung cancer and incorporate biomarker data. 5. Design interventional trials to reduce long-term side-effects. 6. Provide a resource for dissemination and exploitation to the radiotherapy community. Materials and Methods: The central activity of the project is a multicentre, observational study organised through WP2.Enrolment will proceed for 2 years in nine clinical centres, with 2 years follow-up. The primary endpoints are change in breast appearance; rectal bleeding (prostate); pneumonitis (lung). The integrated database will be designed. Blood samples will be collected before radiotherapy. Tracking, biobanking and DNA extraction is handled in WP3. Validation of biomarkers (genetic markers and apoptosis assays) as predictive factors will be carried out in WP4. Some clinical factors have suggested predictive value for radiotherapy side-effects, but there is no consensus. In WP5 these will be validated in existing cohorts. In WP6, predictive models will be used to design clinical interventional trials and produce protocols that seek to lower radiotherapy side-effects in those individuals at high risk of developing them without affecting tumour control. Results: As the project has started in October 2013, no results are available yet. Conclusions: No conclusions can be formulated yet.
Fig.(TOP) Axial and coronal CT slices of the dose region (A,C) and the region outside the dose region but limited to the same lung (B,D). (BOTTOM) The changein HUs between the two regions in the lung Conclusions: The use of high precision treatment in combination with non-invasive micro-CT imaging was found to be a useful quantitative tool in monitoring changes in HU due to RILF.We have shown that partial volume irradiation, more similar to patient irradiation than conventionally used whole body/organ irradiation, induces RILFin mice and can be used to evaluate new treatment strategies.
EP-1820 RAD17 and DNA replication as a potential target for improving radiotherapy in prostate cancer C. Gani1, L. Basler1, D. Ostafichuk2, G. Zafarana2, R.G. Bristow2 1 Eberhard Karls-University Tübingen, Radiation Oncology, Tübingen, Germany 2 Princess Margaret Cancer Centre, Radiation Medicine Program, Toronto, Canada Purpose/Objective: Prostate cancer is the most common non-skin malignancy in men and radiotherapy is a curative modality for clinically localized (but non-indolent) disease. Despite increased precision of
ESTRO 33, 2014 treatment, up to 30% of men with intermediate-risk disease fail radiotherapy due to either localized or systemic resistance. We hypothesized that the status of DNA replication genes may relate to inter-patient radiotherapy response and be a target to improve radiotherapy outcome. Materials and Methods: Using in-house array-CGH on DNA derived from radiotherapy patients’ tumours coupled with in silico RNA expression analyses, we have noted abnormal expression of DNA replication and repair proteins in 10-20% of patients with intermediate risk disease. RAD17 is a master protein involved in the recruitment of the RAD9-RAD1HUS1 (9-1-1) complex to chromatin and activatesthe CHK1 kinase during an S-phase replication cell-cycle checkpoint. To test the functional significance of this clinical genomic finding, we generated a Doxycyclineinducible shRNAi system in 22RV1 prostate cancer cells and analyzed the impact of RAD17 expression on DNA replication and cell proliferation, radiation clonogenic survival and DNA repair foci. Results: We observed a mono-allelic loss of RAD17 in 10% ofpatients which supports studies that test whether lowering levels of RAD17 might sensitize tumours to radiotherapy. By titrating Doxycycline doses we were able to induce a knockdown of RAD17 expression to 50% and 0% relative to the wild-type level. Cells deficient in RAD17 exhibit a significantly decreased growth rate by slowing of S-phase progression. Clonogenic survival assays showed increased sensitivity to ionizing radiation after a knockdown of RAD17 associated with an increased number of residual DNA-DSB repair foci (gamma H2AX and 53BP1). Conclusions: Prostate cancers may have DNA replication abnormalities that could be targeted to reduce prostate cancer radioresistance. These results have implications for the prediction of individualized radiotherapy response and the targeting of abnormal DNA replication as a clinical radiosensitization strategy. (Funded by the Ontario Institute for Cancer Research, the Terry Fox Research Institute, the Canadian Cancer Society and the German Cancer Aid). EP-1821 Prognostic and predictive value of serial plasma Osteopontin levels in the radiotherapy of NSCLC C. Ostheimer1, M. Bache1, A. Güttler1, D. Vordermark1 1 Martin Luther University Halle-Wittenberg, Radiation Oncology, Halle / Saale, Germany Purpose/Objective: Overexpression and elevated plasma levels of the hypoxia-related protein osteopontin (OPN) appear to be a strong prognostic indicator in many malignancies. We recently demonstrated that a co-detection of the hypoxia-related proteins OPN, CA9 and VEGF is more robust in predicting prognosis in the curative-intended radiotherapy for advanced NSCLC than a single plasma marker (Ostheimer et al., Strahlenther Onkol in press). In this prospective clinical study we evaluated the prognostic and predictive value of serial plasma OPN in the curative-intended radiotherapy for NSCLC. Materials and Methods: 69 patients with inoperable NSCLC were prospectively included into the study (55 in M0 and 14 in M1 stage). OPN plasma levels were measured before (t0), at the end (t1) and four weeks after radiotherapy (t2) by enzyme-linked-immuno-sorbent-assay and were correlated with clinicopathological parameters in the entire collective (n=69). The prognostic and predictive power of serial plasma OPN was evaluated in curative-intent (M0) patients who underwent definitive 66-Gy radiotherapy ± chemotherapy. Results: Pre-treatment OPN levels were associated with T-stage (p=.03), lung function (p= .002), weight loss (p=.01), tumor volume (GTV, p=.02) and hemoglobin concentration (p=.04) in the entire patient cohort. M1stage patients had significantly elevated OPN plasma levels at all measurement timepoints compared to M0 patients (p<.0001). Median OPN levels non-significantly decreased from before to after radiotherapy and OPN levels during and after radiotherapy trended to be associated with initial tumor control. Patients with increasing OPN levels after radiotherapy had a significantly reduced freedom-from-relapse (p=.008), overall survival (p=.004) and event-free survival (p=.001) compared to patients with stable or decreasing post-treatment OPN plasma levels. The risk for relapse in patients with increasing or stable OPN levels after radiotherapy was significantly higher compared to patients with decreasing OPN levels after treatment (rr=2.9, p=.01). Increasing posttreatment OPN levels translated into a 3.1-fold increased risk for death as opposed to stable or decreasing OPN plasma levels after treatment (p=.002). Post-treatment OPN plasma levels remained an independent prognostic factor for overall survival (p=.002) in an exploratory multivariate model.
S297 Conclusions: Our results indicate that not absolute but rather OPN level changes over time, particularly in the post-treatment timeframe, may yield additional prognostic and predictive information in the curativeintended radiotherapy for NSCLC. EP-1822 The Radiogenomics Consortium (RGC) C.M.L. West8, B.S. Rosenstein2, S.M. Bentzen3, G.C. Barnett4, A. Dunning5, S.L. Kerns2, J. Chang-Claude6, J.O. Deasy7, C.N. Andreassen1 1 Aarhus University Hospital, Dept. of Experimental Clinical Oncology, Aarhus C, Denmark 2 Mount Sinai Hospital, Icahn School of Medicine, New York, USA 3 University of Maryland, Division of Biostatistics and Bioinformatics, Baltimore, USA 4 Addenbrooke's Hospital, Department of Oncology, Cambridge, United Kingdom 5 Cambridge University, Centre for Cancer Genetic Epidemiology, Cambridge, United Kingdom 6 German Cancer Research Center (DKFZ), Division of Cancer Epidemiology, Heidelberg, Germany 7 Memorial Sloan-Kettering Cancer Centre, Memorial Hospital Research Laboratories, New York, USA 8 University of Manchester, Institute of Cancer Sciences, Manchester, United Kingdom Purpose/Objective: The Radiogenomics Consortium (RGC) was established in 2009. It has approximately 150 members from more than 80 institutions in 19 countries. The purpose of the consortium is to expand the knowledge of the genetic basis for differences in radiosensitivity. The RGC undertakes collaborative projects to identify SNPs associated with adverse effects of radiotherapy, share data and samples, perform meta-analyses, and work together to submit research grant applications. Several collaborative projects have been published. A meta-analysis addressing the impact of the TGFB1 position -509 (rs1800469) SNP upon risk of radiation induced fibrosis after radiotherapy for breast cancer. This study included 2782 patients from 11 different cohorts. Though the study was powered to detect a very small difference in normal tissue complication risk, no association was identified for this SNP (Barnett et al Radiother Oncol 2012). A replicated association between polymorphisms near TNFα and risk of adverse reactions to radiotherapy (Talbot et al. Br J Cancer 2012). A set of reporting guidelines for radiogenomics research have been published (Kerns et al. Radiother Oncol 2013). Other projects are ongoing. A meta-analysis of the impact of the ATM codon 1853 (rs1801516) SNP upon risk of radiation induced toxicity after radiotherapy for breast and prostate cancer. This study included 5434 patients and the preliminary results indicate a small but significant effect of this SNP upon risk of various normal tissue reactions. A metaanalysis of data from four genome wide association studies (RAPPER, RADIOGEN, Gene-PARE, Cross Cancer Institute) addressing toxicity after radiotherapy for prostate cancer (n=1,614) has identified a locus on chr11q22 that is associated with daytime urinary frequency. A multicentre study is attempting to validate previously reported SNP associations in breast cancer patients. The RGC recently obtained 6 million Euros of funding for the REQUITE project from the European Commission's FP7 program. REQUITE aims to prospectively collect clinical data and biological specimens in an observational study of 5300 patients with prostate, breast or lung cancer in order to establish and validate predictive models for normal tissue radiosensitivity. Collaboration has been established with the GameOn OncoArray project that addresses cancer susceptibility and plans to genotype 400,000 cancer patients using a custom made 5000K SNP array. This collaboration offers the RGC the opportunity to do GWAS studies and assess selected SNPs at a very affordable cost. Furthermore, the RGC may have the opportunity to access outcome data from those patients that received radiotherapy. The RGC is open to all investigators interested in studying the relationship between genetic variation and radiation therapy toxicity. To join email [email protected]. EP-1823 Proteome-based identification of biomarkers to predict radiation resistance in cancer patients S. Skvortsov1, P. Eichberger1, I. Skvortsova1, P. Lukas1 1 Innsbruck Medical University, Dept. of Therapeutic Radiology and Oncology, Innsbruck, Austria Purpose/Objective: Radiation therapy plays an important role in the management of malignant tumors, however the problem of radiation resistance resulting in tumor local or distant recurrences after treatment