Radiation therapy is widely used in the treatment of more than half of all cancer patients, and is particularly important in the treatment of brain tumors. For brain tumors, chemotherapy effectiveness is limited by the blood brain barrier; however, radiation therapy effectively reaches brain tumors, and comprises a crucial component of treatment.

Radiation therapy works by damaging DNA and takes advantage of aberrant DNA damage responses in cancer cells that result in cancer cell death. The Floyd Lab focuses on studying mechanisms of DNA damage signaling and repair in brain tumor and other mammalian cells. Specifically, we focus on how chromatin changes mediated by epigenetic modifiers affect the DNA damage response. It is our hope that deeper knowledge regarding the DNA damage response will lead to improved cancer treatments, especially for brain tumor patients. 

Dr. Floyd is a radiation oncologist and brain tumor specialist with first-hand knowledge of the devastating impact of brain tumors and side effects of many current cancer therapies. His lab develops small animal irradiation techniques and mouse models of glioblastoma to test the effects of epigenetic writers and readers on the DDR in more clinically relevant model systems. In this way, we hope to identify strategies to augment tumor cell killing, and/or protect the vital normal tissues for the brain. 

For more information about Project Brainslice, our Tri-Institutional collaboration to model neurological disease, click here.

Over half of all cancer patients receive radiation therapy as part of cancer treatment. For patients with brain tumors, radiation therapy is particularly important because many chemotherapies do not enter the brain well.  Therefore, nearly all brain tumor patients receive radiation therapy. Radiation therapy works by causing DNA damage in tumor cells. We are therefore interested in how normal and malignant cells respond to DNA damage, and by extension, how the DNA damage response (DDR) can be modulated to improve cancer treatment. Specifically, our laboratory has been investigating the effects of epigenetic writers and readers on the signaling network that senses DNA damage and initiates repair, cell cycle arrest and/or cell death.

Clinical Approach: Radiotherapy and Therapeutic DNA Damage

 Scientific Approach and Outcome

Therapeutic Ratio: Exploiting Altered Tumor DNA Damage Repair

Mouse Model of Glioma: Novel Therapeutics

Click here for Dr. Floyd's NCBI bibliography.

Fairchild AT, Salama JK, Wiggins WF, Ackerson BG, Fecci PE, Kirkpatrick JP, Floyd SR, Godfrey DJ. A Deep Learning-Based Computer Aided Detection (CAD) System for Difficult-to-Detect Brain Metastases. Int J Radiat Oncol Biol Phys. 2022 Oct 21;. doi: 10.1016/j.ijrobp.2022.09.068. [Epub ahead of print] PubMed PMID: 36289038.

Mercer-Smith AR, Buckley A, Valdivia A, Jiang W, Thang M, Bell N, Kumar RJ, Bomba HN, Woodell AS, Luo J, Floyd SR, Hingtgen SD. Next-generation Tumor-homing Induced Neural Stem Cells as an Adjuvant to Radiation for the Treatment of Metastatic Lung Cancer. Stem Cell Rev Rep. 2022 Oct;18(7):2474-2493. doi: 10.1007/s12015-022-10375-3. Epub 2022 Apr 19. PubMed PMID: 35441348; NIHMSID:NIHMS1801374.

Satterlee AB, Dunn DE, Valdivia A, Malawsky D, Buckley A, Gershon T, Floyd S, Hingtgen S. Spatiotemporal analysis of induced neural stem cell therapy to overcome advanced glioblastoma recurrence. Mol Ther Oncolytics. 2022 Sep 15;26:49-62. doi:10.1016/j.omto.2022.06.004. eCollection 2022 Sep 15. PubMed PMID: 35784402; PubMed Central PMCID: PMC9217992.

Park C, Buckley ED, Van Swearingen AED, Giles W, Herndon JE, Kirkpatrick JP, Anders CK, Floyd SR. Systemic Therapy Type and Timing Effects on Radiation Necrosis Risk in HER2+ Breast Cancer Brain Metastases Patients Treated With Stereotactic Radiosurgery. Front Oncol. 2022;12:854364. doi: 10.3389/fonc.2022.854364. eCollection 2022. PubMed PMID: 35669439; PubMed Central PMCID: PMC9163666.

Holden R, Park J, Price A, Floyd S, Oldham M. Evaluation of a method to measure fluorescent cell burden in complex culture systems. Biomed Phys Eng Express. 2022 Apr 27;8(3). doi: 10.1088/2057-1976/ac6701. PubMed PMID: 35417904.

Jensen PJ, Torok JA, Goodwin CR, Floyd SR, Wu Q, Wu QJ, Kirkpatrick JP. Purposeful irradiation of the epidural space to enhance local control without compromising cord sparing in spine radiosurgery^†. J Radiosurg SBRT. 2022;8(1):21-26. PubMed PMID: 35387408; PubMed Central PMCID: PMC8930062.

Parsons MW, Peters KB, Floyd SR, Brown P, Wefel JS. Preservation of neurocognitive function in the treatment of brain metastases. Neurooncol Adv. 2021 Nov;3(Suppl 5):v96-v107. doi: 10.1093/noajnl/vdab122. eCollection 2021 Nov. PubMed PMID: 34859237; PubMed Central PMCID: PMC8633744.

Kim GJ, Buckley ED, Herndon JE, Allen KJ, Dale TS, Adamson JD, Lay L, Giles WM, Rodrigues AE, Wang Z, Kelsey CR, Torok JA Jr, Chino JP, Fecci PE, Sampson JH, Anders CK, Floyd SR, Yin FF, Kirkpatrick JP. Outcomes in Patients With 4 to 10 Brain Metastases Treated With Dose-Adapted Single-Isocenter Multitarget Stereotactic Radiosurgery: A Prospective Study. Adv Radiat Oncol. 2021 Nov-Dec;6(6):100760. doi: 10.1016/j.adro.2021.100760. eCollection 2021 Nov-Dec. PubMed PMID: 34934856; PubMed Central PMCID: PMC8655418.

Ge J, Ngo LP, Kaushal S, Tay IJ, Thadhani E, Kay JE, Mazzucato P, Chow DN, Fessler JL, Weingeist DM, Sobol RW, Samson LD, Floyd SR, Engelward BP. CometChip enables parallel analysis of multiple DNA repair activities. DNA Repair (Amst). 2021 Oct;106:103176. doi: 10.1016/j.dnarep.2021.103176. Epub 2021 Jul 10. PubMed PMID: 34365116; PubMed Central PMCID: PMC8439179.

Salama JK, Floyd SR, Willett CG, Kirsch DG. Fostering Radiation Oncology Physician Scientist Trainees Within a Diverse Workforce: The Radiation Oncology Research Scholar Track. Int J Radiat Oncol Biol Phys. 2021 Jun 1;110(2):288-291. doi: 10.1016/j.ijrobp.2020.12.050. Epub 2021 Jan 4. PubMed PMID: 33412263; PubMed Central PMCID: PMC8517888.

Park C, Howell EP, Mehta VA, Ramirez L, Price MJ, Floyd SR, Kirkpatrick JP, Torok J, Abd-El-Barr MM, Karikari IO, Goodwin CR. Patient outcomes and tumor control in single-fraction versus hypofractionated stereotactic body radiation therapy for spinal metastases. J Neurosurg Spine. 2020 Nov 6;:1-10. doi: 10.3171/2020.6.SPINE20349. [Epub ahead of print] PubMed PMID: 33157523.

Edwards DS, Maganti R, Tanksley JP, Luo J, Park JJH, Balkanska-Sinclair E, Ling J, Floyd SR. BRD4 Prevents R-Loop Formation and Transcription-Replication Conflicts by Ensuring Efficient Transcription Elongation. Cell Rep. 2020 Sep 22;32(12):108166. doi: 10.1016/j.celrep.2020.108166. PubMed PMID: 32966794; PubMed Central PMCID: PMC7507985.

Tay IJ, Park JJH, Price AL, Engelward BP, Floyd SR. HTS-Compatible CometChip Enables Genetic Screening for Modulators of Apoptosis and DNA Double-Strand Break Repair. SLAS Discov. 2020 Sep;25(8):906-922. doi: 10.1177/2472555220918367. Epub 2020 May 26. PubMed PMID: 32452708.

Moravan MJ, Fecci PE, Anders CK, Clarke JM, Salama AKS, Adamson JD, Floyd SR, Torok JA, Salama JK, Sampson JH, Sperduto PW, Kirkpatrick JP. Current multidisciplinary management of brain metastases. Cancer. 2020 Apr 1;126(7):1390-1406. doi: 10.1002/cncr.32714. Epub 2020 Jan 23. Review. PubMed PMID: 31971613.

Pant K, Umeh C, Oldham M, Floyd S, Giles W, Adamson J. Comprehensive radiation and imaging isocenter verification using NIPAM kV-CBCT dosimetry. Med Phys. 2020 Mar;47(3):927-936. doi: 10.1002/mp.14008. Epub 2020 Jan 28. PubMed PMID: 31899806.

Barbour AB, Jacobs CD, Williamson H, Floyd SR, Suneja G, Torok JA, Kirkpatrick JP. Radiation Therapy Practice Patterns for Brain Metastases in the United States in the Stereotactic Radiosurgery Era. Adv Radiat Oncol. 2020 Jan-Feb;5(1):43-52. doi: 10.1016/j.adro.2019.07.012. eCollection 2020 Jan-Feb. PubMed PMID: 32051889; PubMed Central PMCID: PMC7004940.

Jain S, Yoon SW, Zhang X, Adamson J, Floyd S, Oldham M. Evaluation of UVA emission from x-ray megavoltage-irradiated tissues and phantoms. Phys Med Biol. 2019 Nov 21;64(22):225017. doi: 10.1088/1361-6560/ab4333. PubMed PMID: 31505474.

Lee HK, Widmayer SJ, Huang MN, Aylor DL, Marchuk DA. Novel Neuroprotective Loci Modulating Ischemic Stroke Volume in Wild-Derived Inbred Mouse Strains. Genetics. 2019 Nov;213(3):1079-1092. doi: 10.1534/genetics.119.302555. Epub 2019 Sep 5. PubMed PMID: 31488517; PubMed Central PMCID: PMC6827375.

Nehama D, Di Ianni N, Musio S, Du H, Patané M, Pollo B, Finocchiaro G, Park JJH, Dunn DE, Edwards DS, Damrauer JS, Hudson H, Floyd SR, Ferrone S, Savoldo B, Pellegatta S, Dotti G. B7-H3-redirected chimeric antigen receptor T cells target glioblastoma and neurospheres. EBioMedicine. 2019 Sep;47:33-43. doi: 10.1016/j.ebiom.2019.08.030. Epub 2019 Aug 26. PubMed PMID: 31466914; PubMed Central PMCID: PMC6796553.

Abisheva Z, Floyd SR, Salama JK, Kirkpatrick J, Yin FF, Moravan MJ, Giles W, Adamson J. The effect of MLC leaf width in single-isocenter multi-target radiosurgery with volumetric modulated arc therapy. J Radiosurg SBRT. 2019;6(2):131-138. PubMed PMID: 31641549; PubMed Central PMCID: PMC6774495.

Lin J, Gresham J, Wang T, Kim SY, Alvarez J, Damrauer JS, Floyd S, Granek J, Allen A, Chan C, Xie J, Owzar K. bcSeq: an R package for fast sequence mapping in high-throughput shRNA and CRISPR screens. Bioinformatics. 2018 Oct 15;34(20):3581-3583. doi: 10.1093/bioinformatics/bty402. PubMed PMID: 29790906; PubMed Central PMCID: PMC6184561.

Lee HK, Koh S, Lo DC, Marchuk DA. Neuronal IL-4Rα modulates neuronal apoptosis and cell viability during the acute phases of cerebral ischemia. FEBS J. 2018 Aug;285(15):2785-2798. doi: 10.1111/febs.14498. Epub 2018 May 24. PubMed PMID: 29756681; PubMed Central PMCID: PMC6105465.

Lam FC, Morton SW, Wyckoff J, Vu Han TL, Hwang MK, Maffa A, Balkanska-Sinclair E, Yaffe MB, Floyd SR, Hammond PT. Enhanced efficacy of combined temozolomide and bromodomain inhibitor therapy for gliomas using targeted nanoparticles. Nat Commun. 2018 May 18;9(1):1991. doi: 10.1038/s41467-018-04315-4. PubMed PMID: 29777137; PubMed Central PMCID: PMC5959860.

Limon D, McSherry F, Herndon J, Sampson J, Fecci P, Adamson J, Wang Z, Yin FF, Floyd S, Kirkpatrick J, Kim GJ. Single fraction stereotactic radiosurgery for multiple brain metastases. Adv Radiat Oncol. 2017 Oct-Dec;2(4):555-563. doi: 10.1016/j.adro.2017.09.002. eCollection 2017 Oct-Dec. PubMed PMID: 29204522; PubMed Central PMCID: PMC5707418.

Jimenez RB, Alexander BM, Mahadevan A, Niemierko A, Rajakesari S, Arvold ND, Floyd SR, Oh KS, Loeffler JS, Shih HA. The impact of different stereotactic radiation therapy regimens for brain metastases on local control and toxicity. Adv Radiat Oncol. 2017 Jul-Sep;2(3):391-397. doi: 10.1016/j.adro.2017.05.008. eCollection 2017 Jul-Sep. PubMed PMID: 29114607; PubMed Central PMCID: PMC5605319.

Kasper E, Ippen F, Wong E, Uhlmann E, Floyd S, Mahadevan A. Stereotactic radiosurgery for brain metastasis from gynecological malignancies. Oncol Lett. 2017 Mar;13(3):1525-1528. doi: 10.3892/ol.2017.5621. Epub 2017 Jan 18. PubMed PMID: 28454285; PubMed Central PMCID: PMC5403471.

Schoenfeld JD, Mahadevan A, Floyd SR, Dyer MA, Catalano PJ, Alexander BM, McDermott DF, Kaplan ID. Ipilmumab and cranial radiation in metastatic melanoma patients: a case series and review. J Immunother Cancer. 2015;3:50. doi: 10.1186/s40425-015-0095-8. eCollection 2015. PubMed PMID: 26672895; PubMed Central PMCID: PMC4678639.

Mahadevan A, Sampson C, LaRosa S, Floyd SR, Wong ET, Uhlmann EJ, Sengupta S, Kasper EM. Dosimetric analysis of the alopecia preventing effect of hippocampus sparing whole brain radiation therapy. Radiat Oncol. 2015 Nov 26;10:245. doi: 10.1186/s13014-015-0555-9. PubMed PMID: 26611656; PubMed Central PMCID: PMC4662000.

Rameseder J, Krismer K, Dayma Y, Ehrenberger T, Hwang MK, Airoldi EM, Floyd SR, Yaffe MB. A Multivariate Computational Method to Analyze High-Content RNAi Screening Data. J Biomol Screen. 2015 Sep;20(8):985-97. doi: 10.1177/1087057115583037. Epub 2015 Apr 27. PubMed PMID: 25918037; PubMed Central PMCID: PMC5377593.

Christ SM, Mahadevan A, Floyd SR, Lam FC, Chen CC, Wong ET, Kasper EM. Stereotactic radiosurgery for brain metastases from malignant melanoma. Surg Neurol Int. 2015;6(Suppl 12):S355-65. doi: 10.4103/2152-7806.163315. eCollection 2015. PubMed PMID: 26392919; PubMed Central PMCID: PMC4553636.

Rangachari D, Yamaguchi N, VanderLaan PA, Folch E, Mahadevan A, Floyd SR, Uhlmann EJ, Wong ET, Dahlberg SE, Huberman MS, Costa DB. Brain metastases in patients with EGFR-mutated or ALK-rearranged non-small-cell lung cancers. Lung Cancer. 2015 Apr;88(1):108-11. doi: 10.1016/j.lungcan.2015.01.020. Epub 2015 Feb 4. PubMed PMID: 25682925; PubMed Central PMCID: PMC4355240.

Dyer MA, Arvold ND, Chen YH, Pinnell NE, Mitin T, Lee EQ, Hodi FS, Ibrahim N, Weiss SE, Kelly PJ, Floyd SR, Mahadevan A, Alexander BM. The role of whole brain radiation therapy in the management of melanoma brain metastases. Radiat Oncol. 2014 Jun 22;9:143. doi: 10.1186/1748-717X-9-143. PubMed PMID: 24954062; PubMed Central PMCID: PMC4132230.

Floyd SR, Pacold ME, Huang Q, Clarke SM, Lam FC, Cannell IG, Bryson BD, Rameseder J, Lee MJ, Blake EJ, Fydrych A, Ho R, Greenberger BA, Chen GC, Maffa A, Del Rosario AM, Root DE, Carpenter AE, Hahn WC, Sabatini DM, Chen CC, White FM, Bradner JE, Yaffe MB. The bromodomain protein Brd4 insulates chromatin from DNA damage signalling. Nature. 2013 Jun 13;498(7453):246-50. doi: 10.1038/nature12147. Epub 2013 Jun 2. PubMed PMID: 23728299; PubMed Central PMCID: PMC3683358.

Weingeist DM, Ge J, Wood DK, Mutamba JT, Huang Q, Rowland EA, Yaffe MB, Floyd S, Engelward BP. Single-cell microarray enables high-throughput evaluation of DNA double-strand breaks and DNA repair inhibitors. Cell Cycle. 2013 Mar 15;12(6):907-15. doi: 10.4161/cc.23880. Epub 2013 Feb 19. PubMed PMID: 23422001; PubMed Central PMCID: PMC3637349.

Floyd SR, Kasper EM, Uhlmann EJ, Fonkem E, Wong ET, Mahadevan A. Hypofractionated Radiotherapy and Stereotactic Boost with Concurrent and Adjuvant Temozolamide for Glioblastoma in Good Performance Status Elderly Patients - Early Results of a Phase II Trial. Front Oncol. 2012;2:122. doi: 10.3389/fonc.2012.00122. eCollection 2012. PubMed PMID: 23087896; PubMed Central PMCID: PMC3472503.

Fonkem E, Uhlmann EJ, Floyd SR, Mahadevan A, Kasper E, Eton O, Wong ET. Melanoma brain metastasis: overview of current management and emerging targeted therapies. Expert Rev Neurother. 2012 Oct;12(10):1207-15. doi: 10.1586/ern.12.111. Review. PubMed PMID: 23082737.

Lu XQ, Mahadevan A, Mathiowitz G, Lin PJ, Thomas A, Kasper EM, Floyd SR, Holupka E, La Rosa S, Wang F, Stevenson MA. Frameless angiogram-based stereotactic radiosurgery for treatment of arteriovenous malformations. Int J Radiat Oncol Biol Phys. 2012 Sep 1;84(1):274-82. doi: 10.1016/j.ijrobp.2011.10.044. Epub 2012 Jan 26. PubMed PMID: 22284685.

Wang CC, Floyd SR, Chang CH, Warnke PC, Chio CC, Kasper EM, Mahadevan A, Wong ET, Chen CC. Cyberknife hypofractionated stereotactic radiosurgery (HSRS) of resection cavity after excision of large cerebral metastasis: efficacy and safety of an 800 cGy × 3 daily fractions regimen. J Neurooncol. 2012 Feb;106(3):601-10. doi: 10.1007/s11060-011-0697-z. Epub 2011 Aug 31. PubMed PMID: 21879395.

Mahadevan A, Floyd S, Wong E, Jeyapalan S, Groff M, Kasper E. Stereotactic body radiotherapy reirradiation for recurrent epidural spinal metastases. Int J Radiat Oncol Biol Phys. 2011 Dec 1;81(5):1500-5. doi: 10.1016/j.ijrobp.2010.08.012. Epub 2010 Oct 13. PubMed PMID: 20950944.

Mahadevan A, Floyd S, Wong E, Chen C, Kasper E. Clinical outcome after hypofractionated stereotactic radiotherapy (HSRT) for benign skull base tumors. Comput Aided Surg. 2011;16(3):112-20. doi: 10.3109/10929088.2011.565160. Epub 2011 Apr 6. PubMed PMID: 21466421.

Floyd SR, Taghian AG. Post-mastectomy radiation in large node-negative breast tumors: does size really matter?. Radiother Oncol. 2009 Apr;91(1):33-7. doi: 10.1016/j.radonc.2008.09.015. Epub 2009 Feb 7. Review. PubMed PMID: 19201501.

Floyd SR, Buchholz TA, Haffty BG, Goldberg S, Niemierko A, Raad RA, Oswald MJ, Sullivan T, Strom EA, Powell SN, Katz A, Taghian AG. Low local recurrence rate without postmastectomy radiation in node-negative breast cancer patients with tumors 5 cm and larger. Int J Radiat Oncol Biol Phys. 2006 Oct 1;66(2):358-64. doi: 10.1016/j.ijrobp.2006.05.001. Epub 2006 Aug 2. PubMed PMID: 16887288.

Taghian AG, Assaad SI, Niemierko A, Floyd SR, Powell SN. Is a reduction in radiation lung volume and dose necessary with paclitaxel chemotherapy for node-positive breast cancer?. Int J Radiat Oncol Biol Phys. 2005 Jun 1;62(2):386-91. doi: 10.1016/j.ijrobp.2004.09.044. PubMed PMID: 15890579.

Floyd SR, Pantanowitz L, McDermott DF, Yannucci J, Driver JA, Stevenson MA, Smith BD, Wilson LD, Richardson PG. Plasma cell problems: Case 1. Disseminated cutaneous plasmacytomas treated with total skin electron radiotherapy. J Clin Oncol. 2005 May 1;23(13):3138-40. doi: 10.1200/JCO.2005.05.175. PubMed PMID: 15860873.

Schmierer K, Grosse P, De Camilli P, Solimena M, Floyd S, Zschenderlein R. Paraneoplastic stiff-person syndrome: no tumor progression over 5 years. Neurology. 2002 Jan 8;58(1):148. doi: 10.1212/wnl.58.1.148. PubMed PMID: 11781426.

Farsad K, Ringstad N, Takei K, Floyd SR, Rose K, De Camilli P. Generation of high curvature membranes mediated by direct endophilin bilayer interactions. J Cell Biol. 2001 Oct 15;155(2):193-200. doi: 10.1083/jcb.200107075. Epub 2001 Oct 15. PubMed PMID: 11604418; PubMed Central PMCID: PMC2198845.

Floyd SR, Porro EB, Slepnev VI, Ochoa GC, Tsai LH, De Camilli P. Amphiphysin 1 binds the cyclin-dependent kinase (cdk) 5 regulatory subunit p35 and is phosphorylated by cdk5 and cdc2. J Biol Chem. 2001 Mar 16;276(11):8104-10. doi: 10.1074/jbc.M008932200. Epub 2000 Dec 11. PubMed PMID: 11113134.

Ferracci F, Fassetta G, Butler MH, Floyd S, Solimena M, De Camilli P. A novel antineuronal antibody in a motor neuron syndrome associated with breast cancer. Neurology. 1999 Sep 11;53(4):852-5. doi: 10.1212/wnl.53.4.852. PubMed PMID: 10489053.

Floyd S, De Camilli P. Endocytosis proteins and cancer: a potential link?. Trends Cell Biol. 1998 Aug;8(8):299-301. doi: 10.1016/s0962-8924(98)01316-6. Review. PubMed PMID: 9704404.

Floyd S, Butler MH, Cremona O, David C, Freyberg Z, Zhang X, Solimena M, Tokunaga A, Ishizu H, Tsutsui K, De Camilli P. Expression of amphiphysin I, an autoantigen of paraneoplastic neurological syndromes, in breast cancer. Mol Med. 1998 Jan;4(1):29-39. PubMed PMID: 9513187; PubMed Central PMCID: PMC2230265.

Members of the Floyd Lab celebrating Dr. Floyd's birthday with an outdoor pizza party

Members of the Floyd Lab celebrating Flannel Friday

Research: 919-684-9344
Patient Care and Clinical Concerns: 919-668-7342

Mailing Address

Floyd Lab
Duke University Medical Center
DUMC Box 103655
Durham, NC 27708

Shipping Address

450 Research Drive
Building: LSRC
Room: B232
Durham, NC 27708