George Blanck

University of South Florida, Tampa, FL, United States

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Publications (43)156.63 Total impact

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    ABSTRACT: The objective of this study was to investigate and quantify the morphological and molecular changes in the thymus for common causes of human infant death. Thymic architecture and molecular changes apparent in human infant head trauma victims were assessed by microscopy and quantified by image analysis of digital whole slide images. Thymuses from victims of SIDS and suffocated infants displaying normal thymus architecture were used for comparison. Molecular expression of proliferation and serotonin receptor and transporter protein markers was evaluated. Duplicate morphological and molecular studies of rodent thymuses were completed with both mouse and rat models. Quantification of novel parameters of digital images of thymuses from human infants suffering mortal head trauma revealed a disruption of the corticomedullary organization of the thymus, particularly involving dissolution of the corticomedullary border. A similar result was obtained for related mouse and rat models. The human thymuses from head trauma cases also displayed a higher percentage of Ki-67-positive thymocytes. Finally, we determined that thymus expression of the human serotonin receptor, and the serotonin transporter, occur almost exclusively in the thymic medulla. Head trauma leads to a disruption of the thymic, corticomedullary border, and molecular expression patterns in a robust and quantifiable manner.
    Technology & Innovation. 01/2014; 16(1).
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    ABSTRACT: A continuing conundrum of cancer biology is the dichotomous function of transcription factors that regulate both proliferation and apoptosis, seemingly opposite results. Previous results have indicated that regulated entry into the S-phase of the cell cycle can be anti-apoptotic. Indeed, tumor suppressor genes can be amplified in tumors and certain, slow growing cancers can represent a relatively poor prognosis, both phenomena likely related to reduced cancer cell apoptosis, in turn due to reduced, unproductive entry into S-phase. In this report, we demonstrate that the Oct-1 transcription factor, commonly considered pro-proliferative, indeed facilitates IFN-γ induced apoptosis in 5637 bladder carcinoma cells, consistent with the role of the retinoblastoma protein in down-regulating Oct-1 DNA binding activity and in suppressing IFN-γ induced apoptosis. More importantly, despite the commonly appreciated process of IFN-γ induced apoptosis, IFN-γ at low concentrations stimulated cell bladder cancer cell proliferation, consistent with apoptosis being dependent on an overstimulation of what is otherwise a pro-proliferative pathway. This observation is in turn consistent with a feed forward mechanism of apoptosis, whereby transcription factors activate proliferation-effector genes at relatively low levels, then apoptosis-effector genes when the transcription factors over-accumulate. Finally, Oct-1 mediated apoptosis is inhibited by co-culture with Raji B-cells, raising the question of whether the normal lymph node environment, or other microenvironments with high concentrations of B-cells, is protective against Oct-1 facilitated apoptosis.
    Experimental and Molecular Pathology 01/2014; · 2.13 Impact Factor
  • James A Mauro, George Blanck
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    ABSTRACT: In cancer biology, most molecular regulatory mechanisms are casually treated as on/off switches for specific cancer hallmarks, despite the lack of compelling evidence that cancer hallmarks can be exclusively attributed to specific regulatory proteins. To consider a novel paradigm for the basis of regulating a set of effector genes for proliferation, versus apoptosis-effector genes, we used a bioinformatics approach to ascertain differences between the transcription factor binding site occurrences in the two sets of genes. Results indicated that there are more binding sites per gene, for transcription factors that regulate both proliferation and apoptosis, among the proliferation-effector genes than among the apoptosis-effector genes. Proliferation-effector genes also had more open chromatin regions. We also applied this paradigm to the question of why p53 and interferon regulatory factor-1 (IRF-1) first activate cell cycle arrest genes followed by apoptosis genes, with results indicating the cycle arrest genes are bigger p53 and IRF-1 traps. These data support the idea that, as a set of transcription factors becomes active, there is a stochastic component leading to the accumulation of these transcription factors on genes that effect an initial phenotype before their accumulation on genes that effect a subsequent phenotype.
    Gene 11/2013; · 2.20 Impact Factor
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    ABSTRACT: Numerous molecular eff ects have been attributed to histone deacetylase inhibitors (HDACI’s), including the induction of major histocompatibility (MHC) genes. Here we report that one FDA approved HDACI, Vorinostat, and a second HDACI currently in clinical trials, Entinostat, reduce the ratio of class II associated invariant peptide (CLIP) to the MHC class II molecule, HLA-DR, indicating an increase in the non-CLIP peptides bound to HLA-DR. The HDACI eff ects are apparent with immortalized B-cells, HLA-DR constitutive melanoma cells and with melanoma cells expressing HLA-DR due to transformation with an expression vector for the HLA-DR gene co-activator, CIITA. Entinostat treatment leads to upregulation of Cathepsin L1, and the HLA-DR peptidome of the Entinostat treated cells is consistent with increased Cathepsin L1 mediated proteolysis. These results indicate that HDACI treatments may alter the HLA-DR peptidome of cells in patients and provide a way to identify novel immunogens for vaccinations and the study of autoantigens.
    Human vaccines 04/2013; 9(4):1-6. · 3.14 Impact Factor
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    ABSTRACT: Numerous molecular effects have been attributed to histone deacetylase inhibitors (HDACI's), including the induction of major histocompatibility (MHC) genes. Here we report that one FDA approved HDACI, Vorinostat, and a second HDACI currently in clinical trials, Entinostat, reduce the ratio of class II associated invariant peptide (CLIP) to the MHC class II molecule, HLA-DR, indicating an increase in the non-CLIP peptides bound to HLA-DR. The HDACI effects are apparent with immortalized B-cells, HLA-DR constitutive melanoma cells and with melanoma cells expressing HLA-DR due to transformation with an expression vector for the HLA-DR gene co-activator, CIITA. Entinostat treatment leads to upregulation of Cathepsin L1, and the HLA-DR peptidome of the Entinostat treated cells is consistent with increased Cathepsin L1 mediated proteolysis. These results indicate that HDACI treatments may alter the HLA-DR peptidome of cells in patients and provide a way to identify novel immunogens for vaccinations and the study of autoantigens.
    Human vaccines & immunotherapeutics. 01/2013; 9(4).
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    ABSTRACT: Genes that fuse to cause cancer have been studied to determine molecular bases for proliferation, to develop diagnostic tools, and as targets for drugs. To facilitate identification of additional, cancer fusion genes, following observation of a chromosomal translocation, we have characterized the genomic features of the fusion gene partners. Previous work indicated that cancer fusion gene partners, are either large or evolutionarily conserved in comparison to the neighboring genes in the region of a chromosomal translocation. These results raised the question of whether large cancer fusion gene partners were also evolutionarily conserved. Methods and We developed two methods for quantifying evolutionary conservation values, allowing the conclusion that both large and small cancer fusion gene partners are more evolutionarily conserved than their neighbors. Additionally, we determined that cancer fusion gene partners have more 3' untranslated region secondary structures than do their neighbors. Coupled with previous algorithms, with or without transcriptome approaches, we expect these results to assist in the rapid and efficient use of chromosomal translocations to identify cancer fusion genes. The above parameters for any gene of interest can be accessed at www.cancerfusiongenes.com.
    Cancer genomics & proteomics. 11/2012; 9(6):389-95.
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    ABSTRACT: The induction of the major histocompatibility (MHC), antigen-presenting class II molecules by interferon-gamma, in solid tumor cells, requires the retinoblastoma tumor suppressor protein (Rb). In the absence of Rb, a repressosome blocks the access of positive-acting, promoter binding proteins to the MHC class II promoter. However, a complete molecular linkage between Rb expression and the disassembly of the MHC class II repressosome has been lacking. By treating A549 lung carcinoma cells with a novel small molecule that prevents phosphorylation-mediated, Rb inactivation, we demonstrate that Rb represses the synthesis of an MHC class II repressosome component, YY1. The reduction in YY1 synthesis correlates with the advent of MHC class II inducibility; with loss of YY1 binding to the promoter of the HLA-DRA gene, the canonical human MHC class II gene; and with increased Rb binding to the YY1 promoter.. These results support the concept that the Rb gene regulatory network (GRN) subcircuit that regulates cell proliferation is linked to a GRN subcircuit regulating a tumor cell immune function.
    Gene 10/2012; · 2.20 Impact Factor
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    ABSTRACT: We tallied the number of possible mutant amino acids in proteins thought to be inactivated early in tumorigenesis and in proteins thought to be inactivated late in tumorigenesis, respectively. Proteins thought to be inactivated early in tumorigenesis, on average, have a greater number of alternative, mutant possibilities, which raises the possibility that the sequential order of mutations associated with cancer development reflects the random chance, throughout life, of a mutagen inactivating a larger versus a smaller target. The hypothesis that the temporal order of genetic changes in cancer reflects mutagen target sizes leads to novel considerations of 1) the mechanisms of the acquisition of cancer hallmarks and 2) cancer screening strategies.
    Genes & cancer 10/2011; 2(10):927-31.
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    ABSTRACT: Numerous cancer fusion genes have been identified and studied, and in some cases, therapy or diagnostic techniques have been designed that are specific to the fusion protein encoded by the fusion gene. There has been little progress, however, in understanding the general features of cancer fusion genes in a way that could provide the foundation for an algorithm for predicting the occurrence of a fusion gene once the chromosomal translocation points have been identified by karyotype analyses. In this study, we used publicly available data sets to characterize 59 cancer fusion genes. The results indicate that all but 17% of the genes involved in fusion events are either relatively large, compared to neighboring genes, or are highly conserved in evolution. These results support a basis for designing algorithms that could have a high degree of predictive value in identifying fusion genes once conventional microscopic analyses have identified the chromosomal breakpoints.
    Cancer genetics and cytogenetics 07/2009; 191(2):78-84. · 1.54 Impact Factor
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    ABSTRACT: Protein inhibitors of activated STATs (PIAS) regulate the interferon-gamma (IFN-gamma) signaling pathway, which has numerous effects on tumor development and tumor cell biology. PIAS's also regulate STAT family members not directly involved in IFN-gamma signaling. This project was designed to assess PIAS1 expression in colon cancer. To determine whether PIAS1, one of the PIAS family members, or IFN-gamma signaling pathway components could be used to stratify colon tumors, we stained tissue microarrays for PIAS1, interferon regulatory factor-1 (IRF-1) and STAT1alpha. PIAS1 staining of the colon cancer tissue microarrays indicated a strong correlation of normal colon cells, and adenomas, with high expression of both PIAS1 and IRF-1. The PIAS1 results in particular may represent a basis for new approaches for efficiently distinguishing adenomas from colon cancer.
    Journal of Cancer Research and Clinical Oncology 04/2009; 135(9):1287-91. · 2.91 Impact Factor
  • Melissa Ihla Niesen, George Blanck
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    ABSTRACT: Major histocompatibility (MHC) class II expression is ordinarily inducible by interferon-gamma (IFN-gamma), but the induction is repressed in retinoblastoma protein (Rb)-defective cells. The repression can be rescued by histone deacetylase (HDAC) inhibitor treatment, but this has never been shown for an HDAC inhibitor that is suitable for clinical trials and eventual patient therapy. Here we demonstrate that the HDAC inhibitor, MS-275, can rescue the IFN-gamma inducibility of human leukocyte antigen (HLA)-DR in non-small cell lung cancer cells. This HDAC inhibitor is currently being tested in phase I/II clinical trials for non-small cell lung cancer. We further verified that the MS-275 effect is related to an HDAC tethered to the HLA-DRA promoter by the transcription factor, YY1. HDAC inhibitors that can be used to treat patients may augment the expression of tumor cell MHC class II, and the results suggest an opportunity to determine the immunological consequences of HDAC inhibitor treatment in tumor therapy.
    Biological & Pharmaceutical Bulletin 04/2009; 32(3):480-2. · 1.85 Impact Factor
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    ABSTRACT: Several advances were established in examining the interaction of transcriptional factors with the HLA-DRA promoter. First, hydrodynamic injection was used to demonstrate the activation of the promoter by class II transactivator in a live mouse. Second, the Oct-1 DNA-binding site in the HLA-DRA promoter is a negative element in many cells, but here we show that Oct-1 activates the promoter independently of the Oct-1-binding site. Third, the retinoblastoma (Rb) protein is required for the induction of the endogenous HLA-DRA gene, due to a poorly understood, pleiotropic effect on the Oct-1 and YY1 repressive functions at the HLA-DRA promoter. There has never been an indication that direct promoter activation, by Rb, is possible. Here, we report that the first HLA-DRA intron has an Rb-responsive element, as indicated by a transient transfection/promoter reporter assay. Finally, RFX activates a methylated version of an HLA-DRA promoter reporter construct, consistent with the role of RFX in rescuing the expression of the methylated, endogenous HLA-DRA gene. Here, we report that this RFX function is not limited to a specific RFX-binding sequence or to the HLA-DRA promoter. These advances provide bases for novel investigations into the function of the major histocompatibility class II promoter.
    Acta Biochimica et Biophysica Sinica 04/2009; 41(3):198-205. · 1.81 Impact Factor
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    ABSTRACT: Neutrophil infiltrates into tumors have been reported in certain circumstances to reduce tumor growth and in other circumstances to augment tumor growth, particularly by facilitating metastasis. Neutrophil chemotaxis can be facilitated by both interleukin-8 (IL-8) and transforming growth factor-beta (TGF-beta). However, the combined effects of these two cytokines on neutrophil tumor infiltrates is unknown, and we considered the possibility that studying the combined effects might resolve apparent contradictions with regard to neutrophil effects on tumor development. First, we determined that a simultaneous IL-8 and TGF-beta blockade is far more efficient at eliminating the neutrophil infiltrate from an A549 derived tumor than is blockade of either cytokine alone. Blockade of IL-8 alone, led to smaller tumors, consistent with the known inhibitory role of TGF-beta on A549 cell proliferation. Blockade of TGF-beta alone rescued the tumor growth but led to reduced metastasis volume. Surprisingly, blockade of both cytokines rescued both tumor volume and metastasis, underscoring the difficulty of understanding the effects of complete tumor cytokine elaboration profiles by isolating the effects of only one cytokine.
    Immunology letters 01/2009; 122(1):26-9. · 2.91 Impact Factor
  • Lijun Xu, Melissa I Niesen, George Blanck
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    ABSTRACT: Gene regulatory network (GRN) subcircuits have been described for cell fate progressions in animal development. The hallmark of these subcircuits is the integration of promoters, and positive- and negative-acting promoter binding proteins, such that an alteration in function of any one member of the defined subcircuit, occurring with a change in cell fate, defines a change in status for all other members of the subcircuit. Here we describe a GRN subcircuit that links a tumor immune function with cell cycle de-regulation. All members of this subcircuit have a predictable status change in response to rescue of the growth-controlled phenotype. Given the similarities between the molecular mechanisms underlying cell status changes in tumorigenesis and development, application of GRN paradigms to tumor progression is particularly apt and offers the hope of providing a more concise, reliable, and therapeutically useful series of predictions linking gene regulation and tumor progression.
    Molecular Immunology 11/2008; 46(4):569-75. · 2.65 Impact Factor
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    ABSTRACT: Numerous human tumor lines fail to induce major histocompatibility (MHC) class II expression following interferon-gamma (IFN-gamma) treatment, a response that is considered to be a normal function for almost all human parenchymal and connective tissue cell-types. The effect of MHC class II non-inducibility on solid tumor growth is controversial, but an extensive body of literature indicates that tumor cell MHC class II expression can lead to an antitumor response or tumor tolerance, depending on a number of variables. Thus, understanding the molecular basis for MHC class II induction failures in solid tumor cells will likely lead to ideas for manipulating the antitumor immune response. To date, a handful of tumor associated molecular anomalies have accounted for all the known failures of MHC class II inducibility. In particular, lack of the retinoblastoma tumor suppressor protein (Rb) has been shown in both human and mouse cells to be strongly associated with failure to induce MHC class II. The basis for this relationship is traceable to, among other things, high level Oct-1 DNA binding activity in Rb-defective cells, which represses the prototypical human MHC class II gene, HLA-DRA. Ordinarily, re-establishment of Rb expression leads to elimination of, or substantially reduced Oct-1 DNA binding activity and to rescue of HLA-DRA inducibility. However, in the case of one non-small cell lung carcinoma line (NSCLC), Rb re-expression failed to rescue HLA-DRA inducibility despite successful re-establishment of Rb-function. We now report that this failure is traceable to the failure of Rb to rescue normal Oct-1 function. Furthermore, histone deacetylase inhibitor treatment allows a bypass of the Rb requirement and facilitates the MHC class II induction in this NSCLC line.
    Molecular Immunology 03/2006; 43(6):710-6. · 2.65 Impact Factor
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    ABSTRACT: The roles of eukaryotic DNA methylation in the repression of mRNA transcription and in the formation of heterochromatin have been extensively elucidated over the past several years. However, the role of DNA methylation in transcriptional activation remains a mystery. In particular, it is not known whether the transcriptional activation of methylated DNA is promoter-specific, depends directly on sequence-specific DNA-binding proteins, or is facilitated by the methylation. Here we report that the sequence-specific DNA-binding protein, RFX, previously shown to mediate the transition from an inactive to an active chromatin structure, activates a methylated promoter. RFX is capable of mediating enhanceosome formation on a methylated promoter, thereby mediating a transition from a methylation-dependent repression of the promoter to a methylation-dependent activation of the promoter. These results indicate novel roles for DNA methylation and sequence-specific DNA-binding proteins in transcriptional activation.
    Journal of Biological Chemistry 12/2005; 280(47):38914-22. · 4.65 Impact Factor
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    ABSTRACT: The cell surface HLA-DR molecule binds foreign peptide antigen and forms an intercellular complex with the T cell receptor in the course of the development of an immune response against or immune tolerance to the antigen represented by the bound peptide. The HLA-DR molecule also functions as a receptor that mediates cell signaling pathways, including as yet poorly characterized pathway(s) leading to apoptosis. Expression of HLA-DR mRNA and protein is ordinarily inducible by interferon-gamma but is not inducible in tumor cells defective for the retinoblastoma tumor suppressor protein (Rb). In the case of the HLA-DRA gene, which encodes the HLA-DR heavy chain, previous work has indicated that this loss of inducibility is attributable to Oct-1 binding to the HLA-DRA promoter. In this report, we used Oct-1 antisense transformants to determine that Oct-1 represses the interferon-gamma response of the endogenous HLA-DRA gene. This determination is consistent with results from a chromatin immunoprecipitation assay, indicating that Oct-1 occupies the endogenous HLA-DRA promoter when the HLA-DRA promoter is inactive in Rb-defective cells but not when the promoter is converted to a previously defined, transcriptionally competent state, induced by treatment of the Rb-defective cells with the HDAC inhibitor, trichostatin A. In vitro DNA-protein binding analyses indicated that Oct-1 prevents HLA-DRA promoter activation by mediating the formation of a complex of proteins, termed DRAN (DRA negative), that blocks NF-Y access to the promoter.
    Journal of Biological Chemistry 08/2004; 279(28):28911-9. · 4.65 Impact Factor
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    George Blanck
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    ABSTRACT: The immune system is capable of interacting with tumor cells in such a way as to lead to tumor cell death, and this knowledge has inspired therapies to manipulate patient immune systems to eradicate cancer. However, tumor cells are able to mitigate the antitumor immune response, a fact that has rarely been addressed in the design of immunotherapies. There are many different tumor cell immune functions that play a role in mitigating the antitumor immune response. In some cases, these functions appear to be intimately associated with the tumor cell abnormalities that lead to loss of growth control, such as the cases where classical tumor suppressor proteins regulate tumor cell immune function genes. In other cases, tumor cell mutations appear to affect only the antitumor response, such as tumor cell mutations that eliminate MHC class I expression. Here I review the bases for tumor cell immune functions, noting in particular where tumor cell mutations, the gold standard for identifying a tumor-specific function, are known to be responsible for the tumor cell immune function. This review also discusses other known regulatory anomalies, in the absence of a known mutation, that are apparently important for tumor development and that regulate tumor cell immune functions. Surprisingly, in many cases where the tumor cell immune function is well understood in terms of its effect on the antitumor immune response, the tumor abnormality underlying the tumor cell immune function is completely uncharacterized.
    Cancer Immunology and Immunotherapy 02/2004; 53(1):1-16. · 3.64 Impact Factor
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    ABSTRACT: Human lymphomas continue to represent a major challenge in oncology, and in particular occur at very high frequencies in AIDS patients. We report here the development of a CD30+ lymphoproliferative disease in mice lacking the proapoptotic transcription factor, interferon regulatory factor-1. These mice most closely represent a model of human anaplastic large-cell lymphoma (ALCL). This mouse model of lymphoma will likely be useful in understanding the development of ALCL and in understanding the development of other closely related CD30+ forms of lymphoma, such as CD30+ Hodgkin's disease and CD30+ cutaneous T-cell lymphoma. This mouse model will also be useful in testing therapies for different forms of CD30+ lymphoma, in particular anti-CD30-based therapies.
    Oncogene 10/2003; 22(40):6166-76. · 8.56 Impact Factor
  • Hongkang Xi, George Blanck
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    ABSTRACT: IFN-gamma induced transcription of class II transactivator (CIITA), a major regulator of MHC class II gene expression, is directed by the CIITA type IV promoter. The IFN-gamma activation of the CIITA type IV promoter is mediated by STAT1 and IRF-1, which bind to the GAS and IRF-E of the promoter, respectively. We and others have determined that IRF-2, another member of the IRF family, also activates the CIITA type IV promoter, by binding to the IRF-E. Also, IRF-2 cooperates with IRF-1 to activate the promoter. DNA binding analyses determined that IRF-1 and IRF-2 can co-occupy the IRF-E of the CIITA type IV promoter. To further understand the mechanism of IRF-1 and IRF-2 cooperativity in the activation of CIITA type IV promoter, we characterized the binding of IRF-1 and IRF-2 to the CIITA IRF-E and mapped the domains of IRF-2 required for the cooperative transactivation. Off-rate experiments revealed that the IRF-2/IRF-E complex was more stable than the IRF-1/IRF-E complex and that the affinity of IRF-1 for the IRF-E was increased when IRF-1 co-occupied the IRF-E with IRF-2. Deletion analysis of functional domains of IRF-2 revealed that a previously described latent activation domain of IRF-2 was essential for IRF-2 transactivation and participated in cooperative activation of the CIITA promoter by IRF-1 and IRF-2. However, the DNA binding domain of IRF-2 was sufficient for cooperativity with IRF-1 in the activation of the CIITA type IV promoter. DNA binding assay demonstrated that, like the full-length IRF-2, the IRF-2 DNA binding domain could co-occupy the CIITA IRF-E with IRF-1.
    Molecular Immunology 02/2003; 39(11):677-84. · 2.65 Impact Factor

Publication Stats

380 Citations
156.63 Total Impact Points

Institutions

  • 1997–2013
    • University of South Florida
      • • Department of Molecular Medicine
      • • Department of Oncologic Sciences
      • • Morsani College of Medicine
      • • Department of Chemistry
      • • Moffitt Cancer Center
      Tampa, FL, United States
  • 2000–2009
    • Moffitt Cancer Center
      • Program in Immunology
      Tampa, Florida, United States