Heart rate-reducing therapy with add-on ivabradine and bisoprolol before coronary computed tomographic angiography in a fast-track ambulatory setting.

Objective This study was performed to determine whether add-on oral ivabradine in patients treated with beta blockers 1 hour before coronary computed tomographic angiography (CCTA) is effective in lowering the heart rate and thus improving CCTA quality. Methods In this single-center cohort study, the data of 294 patients referred for ambulant CCTA were retrospectively screened. Patients with an initial heart rate of ≥75 bpm (n = 112) were pretreated with either a combination of bisoprolol and ivabradine or with bisoprolol alone. Results During the scan, there was no difference in heart rate between the two groups Likewise, there was no significant difference in additionally administered intravenous bradycardic agents, the number of motion artifacts, or the radiation dose. Both drug regimens were tolerated well. Conclusion Additive oral ivabradine 1 hour before CCTA does not result in a further reduction of the heart rate. Consequently, neither movement artifacts nor radiation dose can be reduced. Therefore, pretreatment with ivabradine does not seem reasonably appropriate in an outpatient clinical setting with short patient contact.

3 Tesla breast MR imaging as a problem-solving tool: Diagnostic performance and incidental lesions.

PURPOSE: To investigate the diagnostic performance and incidental lesion yield of 3T breast MRI if used as a problem-solving tool. METHODS: This retrospective, IRB-approved, cross-sectional, single-center study comprised 302 consecutive women (mean: 50±12 years; range: 20-79 years) who were undergoing 3T breast MRI between 03/2013-12/2014 for further workup of conventional and clinical breast findings. Images were read by experienced, board-certified radiologists. The reference standard was histopathology or follow-up ≥ two years. Sensitivity, specificity, PPV, and NPV were calculated. Results were stratified by conventional and clinical breast findings. RESULTS: The reference standard revealed 53 true-positive, 243 true-negative, 20 false-positive, and two false-negative breast MRI findings, resulting in a sensitivity, specificity, PPV, and NPV of 96.4% (53/55), 92.4% (243/263), 72.6% (53/73), and 99.2% (243/245), respectively. In 5.3% (16/302) of all patients, incidental MRI lesions classified BI-RADS 3-5 were detected, 37.5% (6/16) of which were malignant. Breast composition and the imaging findings that had led to referral had no significant influence on the diagnostic performance of breast MR imaging (p>0.05). CONCLUSION: 3T breast MRI yields excellent diagnostic results if used as a problem-solving tool independent of referral reasons. The number of suspicious incidental lesions detected by MRI is low, but is associated with a substantial malignancy rate.

Multiparametric [11C]Acetate positron emission tomography-magnetic resonance imaging in the assessment and staging of prostate cancer.

BACKGROUND: The aim of this study was to evaluate whether MP [11C]Acetate PET-MRI enables an accurate differentiation of benign and malignant prostate tumors as well as local and distant staging. MATERIALS AND METHODS: Fifty-six consecutive patients fulfilling the following criteria were included in this IRB-approved prospective study: elevated PSA levels or suspicious findings at digital rectal examination or TRUS; and histopathological verification. All patients underwent MP [11C]Acetate PET-MRI of the prostate performed on separate scanners with PET/CT using [11C]Acetate and 3T MP MR imaging. Appropriate statistical tests were used to determine diagnostic accuracy, local and distant staging. RESULTS: MP imaging with two MRI parameters (T2w and DWI) achieved the highest sensitivity, specificity, and diagnostic accuracy of 95%, 68.8%, and 88%, with an AUC of 0.82 for primary PCa detection. Neither assessments with a single parameter (AUC, 0.54-0.79), nor different combinations with up to five parameters (AUC, 0.67-0.79) achieved equally good results. MP [11C]Acetate PET-MRI improved local staging with a sensitivity, specificity, and diagnostic accuracy of 100%, 96%, and 97% compared to MRI alone with 72.2%, 100%, and 95.5%. MP [11C]Acetate PET-MRI correctly detected osseous and liver metastases in five patients. CONCLUSIONS: MP [11C]Acetate PET-MRI merges morphologic with functional information, and allows insights into tumor biology. MP [11C]Acetate PET-MRI with two MRI-derived parameters (T2 and DWI) yields the highest diagnostic accuracy. The addition of more parameters does not improve diagnostic accuracy of primary PCa detection. MP [11C]Acetate PET-MRI facilitates improved local and distant staging, providing "one-stop" staging in patients with primary PCa, and therefore has the potential to improve therapy. PATIENT SUMMARY: In this report we investigated MP [11C]Acetate PET-MRI for detection, local and distant staging of prostate cancer. We demonstrate that MP [11C]Acetate PET-MRI with two MRI-derived parameters (T2 and DWI) achieves the best diagnostic accuracy for primary prostate cancer detection and that MP [11C]Acetate PET-MRI enables an improved local and distant staging.

Multiparametric MRI of the prostate at 3 T: limited value of 3D (1)H-MR spectroscopy as a fourth parameter.

PURPOSE: The aim of our study was to assess whether multiparametric magnetic resonance imaging (MP-MRI) of the prostate with three parameters (PS3: T2-weighted, DWI, and DCE) benefits from an additional fourth parameter (PS4: including (1)H-MRSI) in the detection and grading of prostate cancer (PCa) at 3 T. METHODS: MP-MRI was performed in 64 patients (mean 66.7 years, mean PSA 13 ng/ml). Reference standard was obtained by histopathology. Two readers independently evaluated the images. A summation score of each individual parameter for three parameters (PS3) and for four parameters (PS4) was calculated. RESULTS: In 52 (81.3 %) of 64 patients, histopathology confirmed a PCa. The diagnostic performance for PCa detection of PS4 (O1: 91.7 %, O2: 91.3 %) equaled that of PS3 (O1: 92.8 %, O2: 92.2 %, P > 0.05). Prediction of high-grade PCa by PS4 (O1: 75.1 %, O2: 74.7 %) was as good as with PS3 (O1: 75.1 %, O2: 72.8 %, P > 0.05). Kappa agreement between the two readers was substantial (0.734 PS4) to moderate (0.558 PS3). CONCLUSIONS: MP-MRI with four parameters including (1)H-MRSI does not increase the detection and grading of prostate cancer at 3 T compared to MP-MRI with three parameters. A sum score accurately detects PCa at 3 T without an endorectal coil and shows potential for the prediction of tumor grade.

Improved differentiation of benign and malignant breast tumors with multiparametric 18fluorodeoxyglucose positron emission tomography magnetic resonance imaging: a feasibility study.

PURPOSE: To assess whether multiparametric (18)fluorodeoxyglucose positron emission tomography magnetic resonance imaging (MRI) (MP (18)FDG PET-MRI) using dynamic contrast-enhanced MRI (DCE-MRI), diffusion-weighted imaging (DWI), three-dimensional proton MR spectroscopic imaging (3D (1)H-MRSI), and (18)FDG-PET enables an improved differentiation of benign and malignant breast tumors. EXPERIMENTAL DESIGN: Seventy-six female patients (mean age, 55.7 years; range, 25-86 years) with an imaging abnormality (BI-RADS 0, 4-5) were included in this Institutional Review Board (IRB)-approved study. Patients underwent fused PET-MRI of the breast with (18)FDG-PET/CT and MP MRI at 3T. The likelihood of malignancy was assessed for all single parameters, for MP MRI with two/three parameters, and for MP (18)FDG PET-MRI. Histopathology was used as the standard of reference. Appropriate statistical tests were used to assess sensitivity, specificity, and diagnostic accuracy for each assessment combination. RESULTS: There were 53 malignant and 23 benign breast lesions. MP (18)FDG PET-MRI yielded a significantly higher area under the cure (AUC) of 0.935 than DCE-MRI (AUC, 0.86; P = 0.044) and the combination of DCE-MRI and another parameter (AUC, 0.761-0.826; P = 0.013-0.020). MP (18)FDG PET-MRI showed slight further improvement to MP MRI with three parameters (AUC, 0.925; P = 0.317). Using MP (18)FDG PET-MRI there would have been a reduction of the unnecessary breast biopsies recommended by MP imaging with one or two parameters (P = 0.002-0.011). CONCLUSION: This feasibility study shows that MP (18)FDG PET-MRI enables an improved differentiation of benign and malignant breast tumors when several MRI and PET parameters are combined. MP (18)FDG PET-MRI may lead to a reduction in unnecessary breast biopsies.

Molecular imaging for the characterization of breast tumors.

Recently, molecular imaging, using various techniques, has been assessed for breast imaging. Molecular imaging aims to quantify and visualize biological, physiological, and pathological processes at the cellular and molecular levels to further elucidate the development and progression of breast cancer and the response to treatment. Molecular imaging enables the depiction of tumor morphology, as well as the assessment of functional and metabolic processes involved in cancer development at different levels. To date, molecular imaging techniques comprise both nuclear medicine and radiological techniques. This review aims to summarize the current and emerging functional and metabolic techniques for the molecular imaging of breast tumors.

Noninvasive molecular imaging using reporter genes.

Noninvasive reporter gene imaging is a component of molecular imaging. Reporter imaging can provide noninvasive assessments of endogenous biologic processes in living subjects and can be performed using different imaging modalities. This review will focus on radionuclide-based reporter gene imaging as developed and applied in preclinical and clinical studies. Examples of different reporter systems are presented, with a focus on human reporter systems. Selected applications are discussed, including adoptive cell therapies, gene and oncoviral therapies, oncogenesis, signal pathway monitoring, and imaging drug treatment. Molecular imaging, and noninvasive reporter gene imaging in particular, are making important contributions to our understanding of disease development, progression, and treatment in our current era of molecular medicine and individualized patient care.

Combination of pet imaging with viral vectors for identification of cancer metastases.

There are three main ways for dissemination of solid tumors: direct invasion, lymphatic spread and hematogenic spread. The presence of metastases is the most significant factor in predicting prognosis and therefore evidence of metastases will influence decision-making regarding treatment. Conventional imaging techniques are limited in the evaluation and localization of metastases due to their restricted ability to identify subcentimeter neoplastic disease. Hence, there is a need for an effective noninvasive modality that can accurately identify occult metastases in cancer patients. One such method is the combination of positron emission tomography (PET) with vectors designed for delivery of reporter genes into target cells. Vectors expressing the herpes simplex virus-1 thymidine kinase (HSV1-tk) reporter system have recently been shown to allow localization of micrometastases in animal models of cancer using non invasive imaging. Combination of HSV1-tk and PET imaging is based on the virtues of vectors which can carry and selectively express the HSV1-tk reporter gene in a variety of cancer cells but not in normal tissue. A radioactive tracer which is applied systemically is phosphorylated by the HSV1-tk enzyme, and as a consequence, the tracer accumulates in proportion to the level of HSV1-tk expression which can be imaged by PET. In this paper we review the recent developments in molecular imaging of micrometastases using replication-competent viral or nonviral vectors carrying the HSV1-tk gene using PET imaging. These diagnostic paradigms introduce an advantageous new concept in noninvasive molecular imaging with the potential benefits for improving patient care by providing guidance for therapy to patients with risk for metastases.

Treatment algorithm for complex injuries of the foot in paediatric patients.

BACKGROUND: Complex injuries of the foot in the paediatric population present difficult treatment challenges. While standardised protocols exist for the adult population to achieve an optimal result in the treatment of such injuries, therapy in paediatric patientsmust be managed without a firm treatment algorithm. METHODS: Medical records of all patients with a complex trauma of the foot treated at our Department over a period of 13 years were evaluated. A complex trauma of the foot was defined using the scoring system developed by Zwipp et al. (1997).24 Treatment and outcome were analysed. Additionally, our treatment algorithm of complex injuries of the foot in paediatric patients is presented. RESULTS: Twenty-nine patients were included in the study (79%m; 21% f, average age 12.1 years, ranging 2­16 years). Traffic accidents were the most common mechanism (n = 14; 48.3%), followed by a fall from a height in five patients (17.2%). Lawnmower injuries were found in another 3 patients (10.3%) and other mechanisms of injury in 7 patients (24.2%). The mean score according to Zwipp et al. (1997)24 was 5.8 points (range 5­8 points). While closed fractures were diagnosed in 20 (69%) patients, 9 patients (31%) presented open fractures. Operative intervention was necessary in 24 patients (82.8%). Fracture stabilisation could be realised using K-wires in 13 cases (54.2%), screws in 3 cases (12.5%) and plate fixation in 1 case (4.2%). Combined techniques including external fixation were applied in another 7 (29.1%) cases. The mean time between injury and latest follow-up examination was 5.7 years (range 13 months to 13 years). The mean functional outcome was 47.6 (29­56) points for the OAFQ, 15.1 (0­69) points for the FFI and 82.3 (59­100) points for the AOFAS Score. DISCUSSION: To regard the maxims in treating complex injuries and open fractures in the growing skeleton we developed a simple treatment algorithm for complex foot injuries in order to provide preservation of the soft tissue envelope, avoidance of infection, restoration of the axis and the articular surface. CONCLUSION: A complex trauma of the paediatric foot is a rare and challenging injury. Avoidance of infection, preservation of the soft tissue envelope and fracture healing will provide good functional outcome despite the severity of trauma. Long time follow-up is essential to detect complications.

Molecular Imaging in Breast Cancer - Potential Future Aspects.

SUMMARY: Molecular imaging aims to visualize and quantify biological, physiological, and pathological processes at cellular and molecular levels. Recently, molecular imaging has been introduced into breast cancer imaging. In this review, we will present a survey of the molecular imaging techniques that are either clinically available or are being introduced into clinical imaging. We will discuss nuclear imaging and multiparametric magnetic resonance imaging as well as the combined application of molecular imaging in the assessment of breast lesions. In addition, we will briefly discuss other evolving molecular imaging techniques, such as phosphorus magnetic resonance spectroscopic imaging and sodium imaging.

Novel handheld PET probes provide intraoperative localization of PET-avid lymph nodes.

INTRODUCTION: The accurate intraoperative localization of malignant nodes can pose a challenge to the surgical oncologist. Positron emission tomography (PET) scanning has significantly increased our ability to detect suspicious lesions. We investigated the ability of a novel, handheld tool to evaluate suspicious nodes intraoperatively and to correlate its findings with those seen on preoperative PET scan. METHODS: Ten nude rats were inoculated with a lymphogenic mesothelioma tumor line and followed weekly with PET scan studies. When suspicious lymph nodes were found, animals were dissected and the intraoperative amount of tissue radiation was analyzed as "tumor-to-background ratio" (TBR) using the PET probes. RESULTS: The intraoperative probe was used to guide dissections and select high-risk nodes based on their specific radiotracer uptake. A total of 52 nodes were harvested; eight of these were suspicious on preoperative PET scan studies. Using a TBR of 2.5, the intraoperative probes were able to localize all suspicious nodes previously seen on PET scan. Both gamma (sensitivity: 100%; specificity: 86%; positive predictive value (PPV): 57%; negative predictive value (NPV): 100%) and beta (sensitivity: 88%; specificity: 91%; PPV: 64%; NPV: 98%) probes showed an excellent area under the curve (AUC) in the receiver operating characteristic analysis (ROC). Both probes had an AUC of 0.95 for localizing suspicious nodes on PET scan. Furthermore, the AUC for detecting malignancy for the gamma probe was 0.90 (95% confidence interval (CI), 0.83-0.99), and for the beta probe it was 0.97 (95% CI, 0.94-1.0), suggesting a better performance of the beta probe for detecting malignancy. CONCLUSIONS: This novel tool may be used synergistically with the PET scan examination to maximize intraoperative nodal selection and sampling.

Do characteristics of pulmonary nodules on computed tomography in children with known osteosarcoma help distinguish whether the nodules are malignant or benign?

PURPOSE: To determine if selected computed tomography (CT) characteristics of pulmonary nodules in pediatric patients with osteosarcoma can help distinguish the nodules as benign or malignant. METHODS: The institutional review board approved this HIPAA (Health Insurance Portability and Accountability Act-compliant, retrospective study of 30 pediatric osteosarcoma patients (median age 14 years, range 8-22) who underwent chest CT with resection of 117 pulmonary nodules from January 2001 to December 2006. Two pediatric radiologists and one chest radiologist independently and retrospectively reviewed the CT scans and classified nodules as benign, malignant, or indeterminate on the basis of nodule size, laterality, number, location, growth, density, margin appearance, and calcification. Generalized estimating equations were used to examine which characteristics were independent predictors of nodule malignancy. RESULTS: Of the 117 nodules, 80 (68%) were malignant and 37 (32%) were benign by pathologic review. The readers correctly classified 93% to 94% of the malignant nodules. For benign lesions, the results were not as accurate, with the readers correctly classifying only 11% to 30% of lesions. Most of the benign lesions were classified as indeterminate by the readers (54%-65%). Nodule size (≥5 mm) and the presence of calcifications were associated with an increased probability of malignancy (P b .05). CONCLUSION: On chest CT, nodule size 5 mm or greater and the presence of calcifications are associated with an increased probability of malignant nodule histology in pediatric patients with osteosarcoma. However, nodule characteristics, apart from size and calcification, at chest CT cannot reliably distinguish benign from malignant pulmonary nodules in these patients.

Principles and basic concepts of molecular imaging.

Advanced knowledge in molecular biology and new technological developments in imaging modalities and contrast agents calls for molecular imaging (MI) to play a major role in the near future in many human diseases (Weissleder and Mahmood Radiology 219:316-333, 2001). Imaging systems are providing higher signal-to-noise ratio and higher spatial and/or temporal resolution. New specific contrast agents offer the opportunity to drive new challenges for obtaining functional and biological information on tissue characteristics and tissue processes. All this information could be relevant for diagnosis, prognosis and treatment follow-up and to drive local therapies, enhancing local drug/gene delivery. The recent explosion of all these developments is a radical change of perspective in our imaging community because they could have a tremendous impact on our clinical practice and on teaching programs and they call for a more prominent multidisciplinary approach in this field of research.

An analysis of the utility of handheld PET probes for the intraoperative localization of malignant tissue.

INTRODUCTION: The intraoperative localization of suspicious lesions detected by positron emission tomography (PET) scan remains a challenge. To solve this, two novel probes have been created to accurately detect the (18)F-FDG radiotracer intraoperatively. METHODS: Nude rats were inoculated with mesothelioma. When PET scans detected 10-mm tumors, animals were dissected and the PET probes analyzed the intraoperative radiotracer uptake of these lesions as tumor to background ratio (TBR). RESULTS: The 17 suspicious lesions seen on PET scan were localized intraoperatively (by their high TBR) using the PET probes and found malignant on pathology. Interestingly, smaller tumors not visualized on PET scan were detected intraoperatively by their high TBR and found malignant on pathology. Furthermore, using a TBR threshold as low as 2.0, both gamma (sensitivity, 100%; specificity, 80%; positive predictive value (PPV), 96%; and negative predictive value (NPV), 100%) and beta (sensitivity, 100%; specificity, 60%; PPV, 93%; and NPV, 100%) probes reliably detected suspicious lesions on PET scan imaging. They also showed an excellent area under the curve of 0.9 and 0.97 (95% CI of 0.81-0.99 and 0.93-1.0) for gamma and beta probes, respectively, in the receiver operating characteristic analysis for detecting malignancy. CONCLUSION: This novel tool could be used synergistically with a PET scan imaging to maximize tissue selection intraoperatively.

Genetically engineered oncolytic Newcastle disease virus effectively induces sustained remission of malignant pleural mesothelioma.

Malignant pleural mesothelioma is a highly aggressive tumor. Alternative treatment strategies such as oncolytic viral therapy may offer promising treatment options in the future. In this study, the oncolytic efficacy and induction of tumor remission by a genetically engineered Newcastle disease virus [NDV; NDV(F3aa)-GFP; GFP, green fluorescent protein] in malignant pleural mesothelioma is tested and monitored by bioluminescent tumor imaging. The efficacy of NDV(F3aa)-GFP was tested against several mesothelioma cell lines in vitro. Firefly luciferase-transduced MSTO-211H* orthotopic pleural mesothelioma tumor-bearing animals were treated with either single or multiple doses of NDV(F3aa)-GFP at different time points (days 1 and 10) after tumor implantation. Tumor burden was assessed by bioluminescence imaging. Mesothelioma cell lines exhibited dose-dependent susceptibility to NDV lysis in the following order of sensitivity: MSTO-211H > MSTO-211H* > H-2452 > VAMT > JMN. In vivo studies with MSTO-211H* cells showed complete response to viral therapy in 65% of the animals within 14 days after treatment initiation. Long-term survival in all of these animals was >50 days after tumor installation (control animals, <23 d). Multiple treatment compared with single treatment showed a significantly better response (P = 0.005). NDV seems to be an efficient viral oncolytic agent in the therapy of malignant pleural mesothelioma in an orthotopic pleural mesothelioma tumor model.

Different strategies for reducing intestinal background radioactivity associated with imaging HSV1-tk expression using established radionucleoside probes.

One limitation of HSV1-tk reporter positron emission tomography (PET) with nucleoside analogues is the high background radioactivity in the intestine. We hypothesized that endogenous expression of thymidine kinase in bacterial flora could phosphorylate and trap such radiotracers, contributing to the high radioactivity levels in the bowel, and therefore explored different strategies to increase fecal elimination of radiotracer. Intestinal radioactivity was assessed by in vivo microPET imaging and ex vivo tissue sampling following intravenous injection of 18F-FEAU, 124I-FIAU, or 18F-FHBG in a germ-free mouse strain. We also explored the use of an osmotic laxative agent and/or a 100% enzymatically hydrolyzed liquid diet. No significant differences in intestinal radioactivity were observed between germ-free and normal mice. 18F-FHBG-derived intestinal radioactivity levels were higher than those of 18F-FEAU and 124I-FIAU; the intestine to blood ratio was more than 20-fold higher for 18F-FHBG than for 18F-FEAU and 124I-FIAU. The combination of Peptamen and Nulytely lowered intestinal radioactivity levels and increased (2.2-fold) the HSV1-tk transduced xenograft to intestine ratio for 18F-FEAU. Intestinal bacteria in germ-free mice do not contribute to the high intestinal levels of radioactivity following injection of radionucleoside analogues. The combination of Peptamen and Nulytely increased radiotracer elimination by increasing bowel motility without inducing dehydration.

Paracrine regulation of pancreatic cancer cell invasion by peripheral nerves.

BACKGROUND: The ability of cancer to infiltrate along nerves is a common clinical observation in pancreas, head and neck, prostate, breast, and gastrointestinal carcinomas. For these tumors, nerves may provide a conduit for local cancer progression into the central nervous system. Although neural invasion is associated with poor outcome, the mechanism that triggers it is unknown. METHODS: We used an in vitro Matrigel dorsal root ganglion and pancreatic cancer cell coculture model to assess the dynamic interactions between nerves and cancer cell migration and the role of glial cell-derived neurotrophic factor (GDNF). An in vivo murine sciatic nerve model was used to study how nerve invasion affects sciatic nerve function. RESULTS: Nerves induced a polarized neurotrophic migration of cancer cells (PNMCs) along their axons, which was more efficient than in the absence of nerves (migration distance: mean = 187.1 microm, 95% confidence interval [CI] = 148 to 226 microm vs 14.4 microm, 95% CI = 9.58 to 19.22 microm, difference = 143 microm; P < .001; n = 20). PNMC was induced by secretion of GDNF, via phosphorylation of the RET-Ras-mitogen-activated protein kinase pathway. Nerves from mice deficient in GDNF had reduced ability to attract cancer cells (nerve invasion index: wild type vs gdnf+/-, mean = 0.76, 95% CI = 0.75 to 0.77 vs 0.43, 95% CI = 0.42 to 0.44; P < .001; n = 60-66). Tumor specimens excised from patients with neuroinvasive pancreatic carcinoma had higher expression of the GDNF receptors RET and GRFalpha1 as compared with normal tissue. Finally, systemic therapy with pyrazolopyrimidine-1, a tyrosine kinase inhibitor targeting the RET pathway, suppressed nerve invasion toward the spinal cord and prevented paralysis in mice. CONCLUSION: These data provide evidence for paracrine regulation of pancreatic cancer invasion by nerves, which may have important implications for potential therapy directed against nerve invasion by cancer.

Oncolytic vaccinia therapy of squamous cell carcinoma.

BACKGROUND: Novel therapies are necessary to improve outcomes for patients with squamous cell carcinomas (SCC) of the head and neck. Historically, vaccinia virus was administered widely to humans as a vaccine and led to the eradication of smallpox. We examined the therapeutic effects of an attenuated, replication-competent vaccinia virus (GLV-1h68) as an oncolytic agent against a panel of six human head and neck SCC cell lines. RESULTS: All six cell lines supported viral transgene expression (beta-galactosidase, green fluorescent protein, and luciferase) as early as 6 hours after viral exposure. Efficient transgene expression and viral replication (>150-fold titer increase over 72 hrs) were observed in four of the cell lines. At a multiplicity of infection (MOI) of 1, GLV-1h68 was highly cytotoxic to the four cell lines, resulting in > or = 90% cytotoxicity over 6 days, and the remaining two cell lines exhibited >45% cytotoxicity. Even at a very low MOI of 0.01, three cell lines still demonstrated >60% cell death over 6 days. A single injection of GLV-1h68 (5 x 10(6) pfu) intratumorally into MSKQLL2 xenografts in mice exhibited localized intratumoral luciferase activity peaking at days 2-4, with gradual resolution over 10 days and no evidence of spread to normal organs. Treated animals exhibited near-complete tumor regression over a 24-day period without any observed toxicity, while control animals demonstrated rapid tumor progression. CONCLUSION: These results demonstrate significant oncolytic efficacy by an attenuated vaccinia virus for infecting and lysing head and neck SCC both in vitro and in vivo, and support its continued investigation in future clinical trials.

Imaging a Genetically Engineered Oncolytic Vaccinia Virus (GLV-1h99) Using a Human Norepinephrine Transporter Reporter Gene.

PURPOSE: Oncolytic viral therapy continues to be investigated for the treatment of cancer, and future studies in patients would benefit greatly from a noninvasive modality for assessing virus dissemination, targeting, and persistence. The purpose of this study was to determine if a genetically modified vaccinia virus, GLV-1h99, containing a human norepinephrine transporter (hNET) reporter gene, could be sequentially monitored by [(123)I]metaiodobenzylguanidine (MIBG) gamma-camera and [(124)I]MIBG positron emission tomography (PET) imaging. EXPERIMENTAL DESIGN: GLV-1h99 was tested in human malignant mesothelioma and pancreatic cancer cell lines for cytotoxicity, expression of the hNET protein using immunoblot analysis, and [(123)I]MIBG uptake in cell culture assays. In vivo [(123)I]MIBG gamma-camera and serial [(124)I]MIBG PET imaging was done in MSTO-211H orthotopic pleural mesothelioma tumors. RESULTS: GLV-1h99 successfully infected and provided dose-dependent levels of transgene hNET expression in human malignant mesothelioma and pancreatic cancer cells. The time course of [(123)I]MIBG accumulation showed a peak of radiotracer uptake at 48 hours after virus infection in vitro. In vivo hNET expression in MSTO-211H pleural tumors could be imaged by [(123)I]MIBG scintigraphy and [(124)I]MIBG PET 48 and 72 hours after GLV-1h99 virus administration. Histologic analysis confirmed the presence of GLV-1h99 in tumors. CONCLUSION: GLV-1h99 shows high mesothelioma tumor cell infectivity and cytotoxic efficacy. The feasibility of imaging virus-targeted tumor using the hNET reporter system with [(123)I]MIBG gamma-camera and [(124)I]MIBG PET was shown in an orthotopic pleural mesothelioma tumor model. The inclusion of human reporter genes into recombinant oncolytic viruses enhances the potential for translation to clinical monitoring of oncolytic viral therapy.