David L Bartlett

University of Pittsburgh, Pittsburgh, Pennsylvania, United States

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Publications (232)1119.98 Total impact

  • Annals of Surgical Oncology 03/2015; DOI:10.1245/s10434-015-4426-2 · 3.94 Impact Factor
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    ABSTRACT: Quality assessment is an important instrument to ensure optimal surgical outcomes, particularly during the adoption of new surgical technology. The use of the robotic platform for complex pancreatic resections, such as the pancreaticoduodenectomy, requires close monitoring of outcomes during its implementation phase to ensure patient safety is maintained and the learning curve identified. To report the results of a quality analysis and learning curve during the implementation of robotic pancreaticoduodenectomy (RPD). A retrospective review of a prospectively maintained database of 200 consecutive patients who underwent RPD in a large academic center from October 3, 2008, through March 1, 2014, was evaluated for important metrics of quality. Patients were analyzed in groups of 20 to minimize demographic differences and optimize the ability to detect statistically meaningful changes in performance. Robotic pancreaticoduodenectomy. Optimization of perioperative outcome parameters. No statistical differences in mortality rates or major morbidity were noted during the study. Statistical improvements in estimated blood loss and conversions to open surgery occurred after 20 cases (600 mL vs 250 mL [P = .002] and 35.0% vs 3.3% [P < .001], respectively), incidence of pancreatic fistula after 40 cases (27.5% vs 14.4%; P = .04), and operative time after 80 cases (581 minutes vs 417 minutes [P < .001]). Complication rates, lengths of stay, and readmission rates showed continuous improvement that did not reach statistical significance. Outcomes for the last 120 cases (representing optimized metrics beyond the learning curve) included a mean operative time of 417 minutes, median estimated blood loss of 250 mL, a conversion rate of 3.3%, 90-day mortality of 3.3%, a clinically significant (grade B/C) pancreatic fistula rate of 6.9%, and a median length of stay of 9 days. Continuous assessment of quality metrics allows for safe implementation of RPD. We identified several inflexion points corresponding to optimization of performance metrics for RPD that can be used as benchmarks for surgeons who are adopting this technology.
    03/2015; DOI:10.1001/jamasurg.2015.17
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    ABSTRACT: TRAIL has been shown to induce apoptosis in cancer cells, but in some cases, certain cancer cells are resistant to this ligand. In this study, we explored the ability of representative HSP90 (heat shock protein 90) inhibitor NVP-AUY922 to overcome TRAIL resistance by increasing apoptosis in colorectal cancer (CRC) cells. The combination of TRAIL and NVP-AUY922 induced synergistic cytotoxicity and apoptosis, which was mediated through an increase in caspase activation. The treatment of NVP-AUY922 dephosphorylated JAK2 and STAT3 and decreased Mcl-1, which resulted in facilitating cytochrome c release. NVP-AUY922-mediated inhibition of JAK2/STAT3 signaling and down-regulation of their target gene, Mcl-1, occurred in a dose and time-dependent manner. Knock down of Mcl-1, STAT3 inhibitor or JAK2 inhibitor synergistically enhanced TRAIL-induced apoptosis. Taken together, our results suggest the involvement of the JAK2-STAT3-Mcl-1 signal transduction pathway in response to NVP-AUY922 treatment, which may play a key role in NVP-AUY922-mediated sensitization to TRAIL. By contrast, the effect of the combination treatments in non-transformed colon cells was minimal. We provide a clinical rationale that combining HSP90 inhibitor with TRAIL enhances therapeutic efficacy without increasing normal tissue toxicity in CRC patients. Copyright © 2014. Published by Elsevier Inc.
    Cellular Signalling 11/2014; 27(2). DOI:10.1016/j.cellsig.2014.11.013 · 4.47 Impact Factor
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    ABSTRACT: Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemoperfusion (HIPEC) is routinely used to treat certain peritoneal carcinomatoses (PC), but it can be associated with relatively high complication rates, prolonged hospital length of stay, and potential mortality. Our objective was to determine the learning curve (LC) of CRS/HIPEC in our high-volume institution.
    Annals of Surgical Oncology 11/2014; DOI:10.1245/s10434-014-4111-x · 3.94 Impact Factor
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    ABSTRACT: Unresectable colorectal liver metastases remain a major unresolved issue and more effective novel regimens are urgently needed. While screening synergistic drug combinations for colon cancer therapy, we identified a novel multidrug treatment for colon cancer: chemotherapeutic agent melphalan in combination with proteasome inhibitor bortezomib and mTOR (mammalian target of rapamycin) inhibitor rapamycin. We investigated the mechanisms of synergistic antitumor efficacy during the multidrug treatment. All experiments were performed with highly metastatic human colon cancer CX-1 and HCT116 cells, and selected critical experiments were repeated with human colon cancer stem Tu-22 cells and mouse embryo fibroblast (MEF) cells. We used immunochemical techniques to investigate a cross-talk between apoptosis and autophagy during the multidrug treatment. We observed that melphalan triggered apoptosis, bortezomib induced apoptosis and autophagy, rapamycin caused autophagy and the combinatorial treatment-induced synergistic apoptosis, which was mediated through an increase in caspase activation. We also observed that mitochondrial dysfunction induced by the combination was linked with altered cellular metabolism, which induced adenosine monophosphate-activated protein kinase (AMPK) activation, resulting in Beclin-1 phosphorylated at Ser 93/96. Interestingly, Beclin-1 phosphorylated at Ser 93/96 is sufficient to induce Beclin-1 cleavage by caspase-8, which switches off autophagy to achieve the synergistic induction of apoptosis. Similar results were observed with the essential autophagy gene, autophagy-related protein 7, -deficient MEF cells. The multidrug treatment-induced Beclin-1 cleavage was abolished in Beclin-1 double-mutant (D133A/D146A) knock-in HCT116 cells, restoring the autophagy-promoting function of Beclin-1 and suppressing the apoptosis induced by the combination therapy. These observations identify a novel mechanism for AMPK-induced apoptosis through interplay between autophagy and apoptosis.
    Cell Death & Disease 10/2014; 5:e1504. DOI:10.1038/cddis.2014.463 · 5.18 Impact Factor
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    ABSTRACT: Postoperative pancreatic fistulas (POPFs) are potentially morbid complications that often require therapeutic interventions. Distal pancreatectomy performed during cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemoperfusion (HIPEC) puts patients at risk for POPF. The authors hypothesized that POPFs are more severe after CRS/HIPEC than after pancreatectomy alone.
    Annals of Surgical Oncology 10/2014; DOI:10.1245/s10434-014-4186-4 · 3.94 Impact Factor
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    ABSTRACT: Benign duodenal and periampullary tumors are uncommon lesions requiring careful attention to their complex anatomic relationships with the major and minor papillae as well as the gastric outlet during surgical intervention. While endoscopy is less morbid than open resection, many lesions are not amenable to endoscopic removal. Robotic surgery offers technical advantages above traditional laparoscopy, and we demonstrate the safety and feasibility of this approach for a variety of duodenal lesions.
    Journal of Gastrointestinal Surgery 10/2014; 19(2). DOI:10.1007/s11605-014-2668-0 · 2.39 Impact Factor
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    ABSTRACT: A hypoxic tumor microenvironment is characteristic of many cancer types, including one of the most lethal, pancreatic cancer. We recently demonstrated that the receptor for advanced glycation end products (RAGE) has an important role in promoting the development of pancreatic cancer and attenuating the response to chemotherapy. We now demonstrate that binding of RAGE to oncogenic KRAS facilitates hypoxia-inducible factor 1 (HIF1)α activation and promotes pancreatic tumor growth under hypoxic conditions. Hypoxia induces NF-κB-dependent and HIF1α-independent RAGE expression in pancreatic tumor cells. Moreover, the interaction between RAGE and mutant KRAS increases under hypoxia, which in turn sustains KRAS signaling pathways (RAF-MEK-ERK and PI3K-AKT), facilitating stabilization and transcriptional activity of HIF1α. Knock down of RAGE in vitro inhibits KRAS signaling, promotes HIF1α degradation, and increases hypoxia-induced pancreatic tumor cell death. RAGE-deficient mice have impaired oncogenic KRAS-driven pancreatic tumor growth with significant downregulation of the HIF1α signaling pathway. Our results provide a novel mechanistic link between NF-κB, KRAS, and HIF1α, three potent molecular pathways in the cellular response to hypoxia during pancreatic tumor development and suggest alternatives for preventive and therapeutic strategies.
    Cell Death & Disease 10/2014; 5:e1480. DOI:10.1038/cddis.2014.445 · 5.18 Impact Factor
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    ABSTRACT: Single-incision right colectomy has emerged as a safe and feasible alternative to standard laparoscopic resection. As with any new surgical approach, definition of the number of procedures required to optimize the technique is an important goal. Data on this learning curve for single-incision right colectomy are lacking; therefore, we report the outcomes of consecutive single-incision right colectomies to identify the procedural learning curve.
    Surgical Endoscopy 08/2014; DOI:10.1007/s00464-014-3803-4 · 3.31 Impact Factor
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    ABSTRACT: In this study, we attempted to develop a multimodality approach using chemotherapeutic agent mitomycin C, biologic agent tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo-2L), and mild hyperthermia to treat colon cancer. For this study, human colon cancer LS174T, LS180, HCT116 and CX-1 cells were infected with secretory TRAIL-armed adenovirus (Ad.TRAIL) and treated with chemotherapeutic agent mitomycin C and hyperthermia. The combinatorial treatment caused a synergistic induction of apoptosis which was mediated through an increase in caspase activation. The combinational treatment promoted the JNK-Bcl-xL-Bak pathway which transmitted the synergistic effect through the mitochondria-dependent apoptotic pathway. JNK signaling led to Bcl-xL phosphorylation at serine 62, dissociation of Bak from Bcl-xL, oligomerization of Bak, alteration of mitochondrial membrane potential, and subsequent cytochrome c release. Overexpression of dominant-negative mutant of Bcl-xL (S62A), but not dominant-positive mutant of Bcl-xL (S62D), suppressed the synergistic death effect. Interestingly, Beclin-1 was dissociated from Bcl-xL and overexpression of dominant-negative mutant of Bcl-xL (S62A), but not dominant-positive mutant of Bcl-xL (S62D), suppressed dissociation of Beclin-1 from Bcl-xL. A combinatorial treatment of mitomycin C, Ad.TRAIL and hyperthermia induced Beclin-1 cleavage, but the Beclin-1 cleavage was abolished in Beclin-1 double mutant (D133A/D146A) knock-in HCT116 cells, suppressing the apoptosis induced by the combination therapy. We believe that this study supports the application of the multimodality approach to colon cancer therapy.
    APOPTOSIS 08/2014; 19(11). DOI:10.1007/s10495-014-1028-6 · 3.61 Impact Factor
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    ABSTRACT: Baseline carbohydrate antigen 19-9 (CA 19-9) is a useful prognostic marker in pancreatic ductal adenocarcinoma (PDA); however, data on the significance of a change in CA 19-9 following neoadjuvant therapy are lacking. All patients receiving neoadjuvant therapy for PDA from July 2010 to February 2013 were retrospectively reviewed. Resection rate, R0 resection rate, need for venous resection, and overall survival were correlated to CA 19-9 response. Fisher's exact test, Kaplan-Meier survival analysis, and multivariate analysis using Cox regression were used. A total of 78 patients were studied (21 patients with resectable disease, 40 borderline resectable, and 17 with locally advanced disease). A variety of chemotherapies +/- A radiation were utilized during the study period. Overall, 56 patients (72 %) had a decrease in CA 19-9 of > 50 % with neoadjuvant treatment. In borderline resectable patients, CA 19-9 response of > 50 % predicted R0 resection (odds ratio 4.2; p = 0.05). In borderline resectable patients who had an increase in CA 19-9, none of five (0 %) underwent R0 resection compared with 80 % of the remaining cohort (p = 0.001). The complete pathologic response rate was 29 % in patients who had a CA 19-9 response of > 90 % versus 0 % in the remaining patients (p < 0.001). A CA 19-9 response of > 50 % resulted in improved overall survival (28.0 vs. 11.1 months; p < 0.0001) and was an independent predictor of survival (hazard ratio 0.26; 95 % CI 0.13-0.55; p < 0.0001). CA 19-9 response to neoadjuvant therapy is associated with R0 resection rate, histopathologic response, and survival. Incorporation of this easily obtainable biomarker into future clinical trials may facilitate more rapid evaluation of novel regimens.
    Annals of Surgical Oncology 08/2014; 21(13). DOI:10.1245/s10434-014-3842-z · 3.94 Impact Factor
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    ABSTRACT: We analyzed a series of 55 disseminated appendiceal mucinous neoplasms treated at our institution for GNAS and KRAS mutations in an attempt to correlate mutation status with clinicopathologic findings and patient survival. GNAS mutations (p.R201H, c.602G > A and p.R201C, c.602C > T) were identified in 17/55 (31%) of disseminated mucinous neoplasms and were found in 8/23 (35%) low-grade mucinous neoplasms, 7/19 (37%) high-grade mucinous adenocarcinomas lacking a signet ring cell component, and 2/13 (15%) high-grade mucinous adenocarcinomas with a signet ring cell component. All seven mucinous adenocarcinomas composed of pure (>95%) signet ring cells harbored wild-type GNAS. There was no significant association between GNAS mutations and gender and age (both with p > 0.05) or between GNAS mutations and individual adverse histologic features including cytologic grade, destructive invasion, tumor cellularity, angiolymphatic invasion, perineural invasion, and signet ring cells (all with p > 0.05). KRAS mutations were identified in 22/55 (40%) disseminated mucinous neoplasms. GNAS-mutated disseminated appendiceal mucinous neoplasms more frequently harbored concurrent KRAS mutations compared with GNAS-wild-type tumors (65% vs. 29%, p = 0.018). GNAS mutations were not significantly associated with overall survival (both with p > 0.05). Only overall tumor grade was an independent predictor of overall survival in the multivariable analysis (p = 0.01). Our results indicate that GNAS mutations are frequently identified in both low-grade and high-grade disseminated appendiceal mucinous neoplasms indicating that GNAS mutation status cannot be used to distinguish between low-grade from high-grade appendiceal mucinous neoplasms.
    Human pathology 08/2014; 45(8). DOI:10.1016/j.humpath.2014.04.018 · 2.81 Impact Factor
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    ABSTRACT: Inflammation plays a central role in peritoneal carcinomatosis (PC) etiology and progression, and circulating levels of inflammatory biomarkers prior to surgery predict progression-free and overall survival in PC patients. Depression and fatigue are prevalent among PC patients, and experimental research shows that these symptoms may be mediated by proinflammatory cytokines. As yet unstudied is the possibility that the heightened levels of inflammatory markers in PC patients may contribute to their experience of common neurovegetative symptoms.
    Brain Behavior and Immunity 07/2014; 42. DOI:10.1016/j.bbi.2014.06.019 · 5.61 Impact Factor
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    Z S Guo, D L Bartlett
    Cancer Gene Therapy 07/2014; 21(7):261-3. DOI:10.1038/cgt.2014.31 · 2.55 Impact Factor
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    ABSTRACT: Obesity has been described as a risk factor for surgical complications and may play a prominent role in the progression, recurrence, and survival rates of various cancers. Our objective was to investigate the impact of being overweight or obese on perioperative and oncologic outcomes after cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemoperfusion (HIPEC) for peritoneal carcinomatosis (PC) from mucinous appendiceal neoplasms (MAN). From a prospectively maintained database (2001-2010) of CRS/HIPEC for PC from MAN, we evaluated the body mass index (BMI) of patients, categorizing them into normal weight (NW < 25 kg/m(2)), overweight (OW = 25 to 29.9 kg/m(2)), and obese (OB a parts per thousand yen 30 kg/m(2)). We compared the perioperative and oncologic outcomes among groups. Of the 282 patients in the database, 234 had BMI data available, and 81, 79, and 74 patients were categorized as NW, OW, and OB, respectively. Although there was a trend toward increased risk of overall complications, wound infections, deep vein thrombosis, respiratory and renal complications, and anastomotic leaks in the OW and OB groups, these differences only achieved statistical significance for renal (p = 0.03) and pulmonary (p = 0.02) complications in the OW and OB groups, respectively. The 5-year survival rate for NW, OW, and OB patients was 63.9, 48, and 54.4 %, respectively (p = 0.63). The median time to progression was 21.1 (NW), 21.7 (OW), and 23.9 (OB) months (p = 0.83). OW and OB patients may have an increased risk of renal and pulmonary complications, respectively. Obesity has no major impact on perioperative mortality and long-term oncologic outcomes in patients undergoing CRS/HIPEC for MAN.
    Annals of Surgical Oncology 06/2014; 21(12). DOI:10.1245/s10434-014-3807-2 · 3.94 Impact Factor
  • Shirin Sabbaghian, David Bartlett, Allan Tsung
    Gastroenterology 05/2014; 146(5):S-1021. DOI:10.1016/S0016-5085(14)63715-X · 13.93 Impact Factor
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    Zong Sheng Guo, Zuqiang Liu, David L Bartlett
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    ABSTRACT: Oncolytic viruses (OVs) are novel immunotherapeutic agents whose anticancer effects come from both oncolysis and elicited antitumor immunity. OVs induce mostly immunogenic cancer cell death (ICD), including immunogenic apoptosis, necrosis/necroptosis, pyroptosis, and autophagic cell death, leading to exposure of calreticulin and heat-shock proteins to the cell surface, and/or released ATP, high-mobility group box 1, uric acid, and other damage-associated molecular patterns as well as pathogen-associated molecular patterns as danger signals, along with tumor-associated antigens, to activate dendritic cells and elicit adaptive antitumor immunity. Dying the right way may greatly potentiate adaptive antitumor immunity. The mode of cancer cell death may be modulated by individual OVs and cancer cells as they often encode and express genes that inhibit/promote apoptosis, necroptosis, or autophagic cell death. We can genetically engineer OVs with death-pathway-modulating genes and thus skew the infected cancer cells toward certain death pathways for the enhanced immunogenicity. Strategies combining with some standard therapeutic regimens may also change the immunological consequence of cancer cell death. In this review, we discuss recent advances in our understanding of danger signals, modes of cancer cell death induced by OVs, the induced danger signals and functions in eliciting subsequent antitumor immunity. We also discuss potential combination strategies to target cells into specific modes of ICD and enhance cancer immunogenicity, including blockade of immune checkpoints, in order to break immune tolerance, improve antitumor immunity, and thus the overall therapeutic efficacy.
    Frontiers in Oncology 04/2014; 4:74. DOI:10.3389/fonc.2014.00074
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    ABSTRACT: Immunization with effective cancer vaccines can offer a much needed adjuvant therapy to fill the treatment gap after liver resection to prevent relapse of hepatocellular carcinoma (HCC). However, current HCC cancer vaccines are mostly based on native shared-self/tumor antigens that are only able to induce weak immune responses. In this study, we investigated whether the HCC-associated self/tumor antigen of alpha-fetoprotein (AFP) could be engineered to create an effective vaccine to break immune tolerance and potently activate CD8 T cells to prevent clinically relevant carcinogen-induced autochthonous HCC in mice. We found that the approach of computer-guided methodical epitope-optimization created a highly immunogenic AFP and that immunization with lentivector expressing the epitope-optimized AFP, but not wild-type AFP, potently activated CD8 T cells. Critically, the activated CD8 T cells not only cross-recognized short synthetic wild-type AFP peptides, but also recognized and killed tumor cells expressing wild-type AFP protein. Immunization with lentivector expressing optimized AFP, but not native AFP, completely protected mice from tumor challenge and reduced the incidence of carcinogen-induced autochthonous HCC. In addition, prime-boost immunization with the optimized AFP significantly increased the frequency of AFP-specific memory CD8 T cells in the liver that were highly effective against emerging HCC tumor cells, further enhancing the tumor prevention of carcinogen-induced autochthonous HCC. Our data demonstrate that epitope-optimization is required to break immune tolerance and potently activate AFP-specific CD8 T cells, generating effective antitumor effect to prevent clinically relevant carcinogen-induced autochthonous HCC in mice. Our study provides a practical roadmap to develop effective human HCC vaccines that may result in an improved outcome compared to the current HCC vaccines based on wild-type AFP. (Hepatology 2013;).
    Hepatology 04/2014; 59(4). DOI:10.1002/hep.26893 · 11.19 Impact Factor
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    Stephanie Downs-Canner, David L Bartlett
    Annals of Surgical Oncology 03/2014; 21(7). DOI:10.1245/s10434-014-3660-3 · 3.94 Impact Factor
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    ABSTRACT: Previous studies have demonstrated that the prognosis of disseminated mucinous appendiceal neoplasms is highly dependent upon tumor grade. Reflecting this, the 7th edition of the American Joint Committee on Cancer (AJCC) staging system now incorporates a three-tier grading system for prognostic staging of mucinous appendiceal tumors. However, the grading criteria are not well described. In order to address this issue, we evaluated clinicopathologic and molecular features of 219 cases from 151 patients with widely disseminated appendiceal mucinous neoplasia treated at our institution between 2004 and 2012. We identified histologic features that were associated with worse overall survival on univariate analysis: destructive invasion, high cytologic grade, high tumor cellularity, angiolymphatic invasion, perineural invasion, and signet ring cell component (all with P<0.0001). We used these morphologic characteristics to classify neoplasms into three grades: AJCC grade G1 lacked all adverse histologic features; AJCC grade G2 had at least one adverse histologic feature (except a signet ring cell component); and AJCC grade G3 were defined by the presence of a signet ring cell component. Patients with AJCC grade G2 and grade G3 adenocarcinomas had a significantly worse prognosis compared with AJCC grade G1 (P<0.0001 for each). A trend toward worse overall survival was identified for patients with AJCC grade G3 adenocarcinomas compared with AJCC grade G2 adenocarcinomas (P=0.07). Our multivariate analysis found that this three-tier grading system was a significant predictor of outcome (P=0.008), independent of other prognostic variables. After controlling for other prognostic variables, AJCC grade G2 was associated with a 2.7-fold increased risk of death (95% confidence interval (CI), 1.2-6.2) and AJCC grade G3 was associated with a 5.1-fold increased risk of death (95% CI, 1.7-14) relative to grade G1 tumors. Our results indicate that evaluation of a limited set of adverse histologic features allows for the separation of disseminated mucinous neoplasms of appendiceal origin into three morphologically defined and prognostically relevant grades as advocated by the AJCC.Modern Pathology advance online publication, 14 March 2014; doi:10.1038/modpathol.2014.37.
    Modern Pathology 03/2014; DOI:10.1038/modpathol.2014.37 · 6.36 Impact Factor

Publication Stats

5k Citations
1,119.98 Total Impact Points

Institutions

  • 2003–2015
    • University of Pittsburgh
      • • Division of Surgical Oncology
      • • Pittsburgh Cancer Institute
      • • Department of Surgery
      Pittsburgh, Pennsylvania, United States
  • 2013
    • Georgia Regents University
      • Department of Radiology
      Augusta, GA, United States
  • 2012
    • Gulhane Military Medical Academy
      Engüri, Ankara, Turkey
    • Krankenhaus Barmherzige Brüder Regensburg
      Ratisbon, Bavaria, Germany
    • University of Florida
      Gainesville, Florida, United States
  • 2011
    • Southern Medical University
      • Department of Immunology
      Guangzhou, Guangdong Sheng, China
  • 1999–2011
    • National Cancer Institute (USA)
      • • Surgery Branch
      • • Center for Cancer Research
      Maryland, United States
    • Technische Universität München
      München, Bavaria, Germany
  • 1997–2009
    • National Institutes of Health
      • • Branch of Surgery
      • • Section on Human Iron Metabolism
      Maryland, United States
  • 2004
    • UPMC
      Pittsburgh, Pennsylvania, United States
  • 2001–2002
    • National Institute of Allergy and Infectious Diseases
      베서스다, Maryland, United States
    • Cancer Research and Biostatistics
      Seattle, Washington, United States
  • 1996
    • University of Pennsylvania
      • Department of Surgery
      Philadelphia, Pennsylvania, United States