5-Fluorouracil and gemcitabine potentiate the efficacy of oncolytic herpes viral gene therapy in the treatment of pancreatic cancer

Oncolytic herpes viruses are attenuated, replication-competent viruses that selectively infect, replicate within, and lyse cancer cells and are highly efficacious in the treatment of a wide variety of experimental cancers. The current study seeks to define the pharmacologic interactions between chemotherapeutic drugs and the oncolytic herpes viral strain NV1066 in the treatment of pancreatic cancer cell lines. The human pancreatic cancer cell lines Hs 700T, PANC-1, and MIA P_aC_a-2 were treated in vitro with NV1066 at multiplicities of infection (MOI; ratio of the number of viral particles per tumor cell) ranging from 0.01 to 1.0 with or without 5-fluorouracil (5-FU) or gemcitabine. Synergistic efficacy was determined by the isobologram and combination-index methods of Chou and Talalay. Viral replication was measured using a standard plaque assay. Six days after combination therapy, 76% of Hs 700T cells were killed compared with 43% with NV1066 infection alone (MOI = 0.1) or 0% with 5-FU alone (2 βmol/L) (P < .01). Isobologram and combination-index analyses confirmed a strongly synergistic pharmacologic interaction between the agents at all viral and drug combinations tested (LD5 to LD95) in the three cell lines. Dose reductions up to 6- and 78-fold may be achieved with combination therapy for NV1066 and 5-FU, respectively, without compromising cell kill. 5-FU increased viral replication up to 19-fold compared with cells treated with virus alone. Similar results were observed by combining gemcitabine and NV1066. We have demonstrated that 5-FU and gemcitabine potentiate oncolytic herpes viral replication and cytotoxicity across a range of clinically achievable doses in the treatment of human pancreatic cancer cell lines. The potential clinical implications of this synergistic interaction include improvements in efficacy, treatment-associated toxicity, tolerability of therapeutic regimens, and quality of life. These data provide the cellular basis for the clinical investigation of combined oncolytic herpes virus therapy and chemotherapy in the treatment of pancreatic cancer. Presented at the Forty-Sixth Annual Meeting of The Society for Surgery of the Alimentary Tract, Chicago, Illinois, May 141-18, 2005 (oral presentation). Supported in part by training grant T 32 CA09501 (D.P.E. and K.J.H.), AACR-AstraZeneca Cancer Research and Prevention fellowship (P.S.A), grants RO1 CA 76416 and RO1 CA/DK80982 (Y.F.) from the National Institutes of Health, grant BC024118 from the U.S. Army (Y.F.), grant IMG0402501 from the Susan G. Komen Foundation (Y.F.), and grant 032047 from Flight Attendant Medical Research Institute (Y.F.).     

The replication-competent oncolytic herpes simplex mutant virus NV1066 is effective in the treatment of esophageal cancer

BACKGROUND: The oncolytic herpes simplex-1 virus, NV1066, is a replication-competent virus that has been engineered to infect and lyse tumor cells selectively and to carry a transgene for enhanced green fluorescent protein (EGFP). The purpose of this study was to determine viral cytotoxicity in an esophageal cancer cell line and to determine whether EGFP expression could be used as a marker of viral infection. METHODS: BE3 esophageal adenocarcinoma cells were infected with NV1066 in vitro to determine cell kill and viral replication. EGFP expression was assessed by flow cytometry. The in vivo anti-tumor activity of NV1066 was tested in subcutaneous and intraperitoneal xenograft models. EGFP expression was localized in vivo by fluorescent microscopy and fluorescent laparoscopy. RESULTS: NV1066 effectively replicated within and killed BE3 cells in vitro and in vivo. EGFP expression identified infected tumor cells. After NV1066 treatment in vivo, EGFP expression localized to the tumor. In an intraperitoneal tumor model, EGFP could be visualized endoscopically using a laparoscope with a fluorescent filter. CONCLUSIONS: NV1066 has oncolytic activity against the BE3 cell line and may be a useful therapy against esophageal cancer. EGFP expression localizes the virus and may help to identify tumor deposits in vivo. Oncolytic activity with NV1066 against gastrointestinal cancers may potentially be tracked by endoscopy.     

Interleukin 12 secretion enhances antitumor efficacy of oncolytic herpes simplex viral therapy for colorectal cancer

OBJECTIVE: To assess the strategy of combining oncolytic herpes simplex virus (HSV) therapy with immunomodulatory therapy as treatment for experimental colon cancer. The oncolytic HSV recombinant NV1023 and the interleukin 12 (IL-12)-secreting oncolytic NV1042 virus were evaluated in vitro and in vivo with respect to antitumor efficacy. SUMMARY BACKGROUND DATA: Genetically engineered, replication-conditional, attenuated HSVs have shown oncolytic activity against a wide variety of solid malignancies. Other strategies for treating cancer have involved immunomodulation and cytokine gene transfer using viral vectors. This study has combined both of these strategies by inserting the murine IL-12 gene into a replication-competent HSV. This approach allows oncolytic therapy to replicate selectively within and lyse tumor cells while providing the host immune system with the cytokine stimulus necessary to recruit and activate inflammatory cells needed to enhance the antitumor effect. METHODS: NV1023 is a multimutant HSV based on the wild-type HSV-1 F strain. NV1042 was created by insertion of the mIL-12 gene into NV1023. Cytotoxicity and viral proliferation of both NV1023 and NV1042 within murine CT26 colorectal cancer cells were first shown. Cells infected with NV1042 were then shown to produce significant levels of IL-12. Using an experimental flank model of colon cancer, mice were treated with both high and low doses of NV1023 or NV1042 and were followed up for both cure and reduction in tumor burden. RESULTS: Both viruses could replicate within and kill CT26 cells in vitro, with 100% cytotoxicity achieved after infection by either virus. Only NV1042 could produce mIL-12. Therapy using high viral doses to treat animals in vivo showed equal efficacy between NV1023 and NV1042, with five of seven cures for each virus. When viral doses were lowered, only the cytokine-producing NV1042 virus could reduce tumor burden and cure animals of their disease. CONCLUSIONS: Both NV1023 and NV1042 have the oncolytic potential to kill colon cancer cells at higher doses. Cytokine production by NV1042 may allow lower doses of viral therapy to be used without losing antitumor efficacy. The combination of oncolytic viral therapy and immunomodulatory strategies should be further investigated as treatment for colon cancer.     

Use of an oncolytic virus secreting GM-CSF as combined oncolytic and immunotherapy for treatment of colorectal and hepatic adenocarcinomas

BACKGROUND: Oncolytic cancer therapy using herpes simplex viruses (HSV) that have direct tumoricidal effects and cancer immunotherapy using the cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) have each been effective in preclinical testing. NV1034 is a multimutated oncolytic HSV carrying the gene for murine GM-CSF that attempts to combine these 2 anticancer strategies. The purpose of this study was to compare NV1034 to NV1023, the parent HSV mutants lacking GM-CSF, to determine if such combined oncolytic and immunotherapy using a single vector has advantages over oncolytic therapy alone. METHODS: Expression GM-CSF in vitro did not alter the infectivity, cytotoxicity, or replication of NV1034 compared to the noncytokine-secreting control. Tumors infected with NV1034 produced GM-CSF in picogram quantities. In vivo efficacy of the viruses against murine colorectal carcinoma CT26 and murine hepatoma Hepa l-6 was then tested in subcutaneous tumors in syngeneic Balb/c and C57 L/J mice, respectively. In these immune-competent models, NV1034 and NV1023 each demonstrated potent antitumor activity. RESULTS: Treatment with NV1034 had significantly better antitumor effect compared to treatment with NV1023. Furthermore, there was no difference in the antitumor efficacy of these viruses in mice depleted of CD4+ and CD8+ T lymphocytes. CONCLUSIONS: Viral vectors combining oncolytic and immunotherapy are promising agents in treatment of colorectal carcinoma and hepatoma.     

The effect of hyperthermia on mitomycin-C induced cytotoxicity in four human bladder cancer cell lines

INTRODUCTION: Hyperthermia and mitomycin-C (MMC) have given very encouraging results in several clinical studies for the treatment of superficial transitional cell carcinoma of the bladder. However, a synergistic effect of hyperthermia and MMC on the decrease of cell proliferation has never been demonstrated accurately in vitro. We investigated the effect of MMC versus MMC combined with hyperthermia on the cytotoxicity in four human bladder cancer cell lines. MATERIAL AND METHODS: The RT112, RT4, 253J and T24 human bladder cancer cell lines were seeded in 96-well microtiter plates at 2.0 x 10(4) cells per well and were left to attach for 24 hours. The cells were then treated for 60 minutes with MMC concentrations ranging from 0 to 400 microg/ml at a temperature of 37 degrees C or 43 degrees C. After treatment cells were rinsed three times with culture medium and left for 24 hours in the incubator. Dimethyl thiazolyl tetrazolium (MTT) solution was added and after 4 hours of incubation the MTT containing media was aspired from all wells and 100 microl of dimethyl sulfoxide was added to each well. A spectrum analyses was performed at 595 nm light wavelength. RESULTS: A decrease of cell proliferation after treatment with increasing concentrations MMC was demonstrated. Hyperthermia has a synergistic effect on the decrease of cell proliferation by different concentrations MMC. In the cells treated without MMC no significant difference in the extent of cell killing at 37 degrees C and 43 degrees C was observed. Furthermore, no difference was observed between cells with a p53 protein mutation (RT112 and T24) or without a p53 protein mutation (253J and RT4). Conclusion: A clear synergistic effect of MMC and hyperthermia has been demonstrated in four human bladder cancer cell lines.     

Systemic mitomycin C versus cisplatin: comparison of antitumor activity in primary murine bladder cancer

The FANFT-induced bladder cancer murine model was used to evaluate the effect of DDP and MMC on the incidence and size of subsequent tumors. MMC was at least equally effective as DDP in inhibiting tumor growth in this model. There was no apparent synergistic effect when the two agents were combined although toxicity was increased. Further clinical trials with systemic MMC for locally advanced or metastatic urothelial transitional cell carcinoma appear to be indicated.     

Epidermal growth factor receptor targeting of replication competent adenovirus enhances cytotoxicity in bladder cancer

PURPOSE: We evaluated the delivery and oncolytic potential of targeted replication competent adenoviruses in bladder cancer lines. MATERIALS AND METHODS: Seven established human bladder cancer tumor lines (5637, SW800, TCCsup, J82, Scaber, T24 and 253J) were studied for the expression of integrins alpha(v)beta3, alpha(v)beta5, Coxsackievirus and adenovirus receptor, epidermal growth factor receptor (EGF-R) and epithelial cell adhesion molecule antigens using flow cytometry analysis. Bispecific single chain Fv fragments were used to target replication deficient luciferase reporter adenovirus to EGF-R (425-s11) or to epithelial cell adhesion molecule (C28-s11) antigens. Moreover, a fiber modified adenovirus targeting alpha(v)-integrins was studied. Replication competent serotype-5 adenoviruses attenuated to replicate specifically in retinoblastoma pRb (Ad5-d24) or p53 deficient (Ad5-d55K) cells were tested in vitro for oncolytic properties. RESULTS: Low to absent Coxsackievirus and adenovirus receptor expression was found in 5 of the 7 tumor lines (SW800, J82, T24, 5637 and Scaber). EGF-R expression was found in all cell lines, whereas elevated epithelial cell adhesion molecule expression was seen in 3 (5637, Scaber and TCCsup), alpha(v)beta3-integrin was found in 1 (Scaber) and alpha(v)beta5-integrin was found in 3 (TCCsup, 253J and T24). EGF-R targeting using 425-s11 improved transgene expression in all cell lines from 2.1 to 12.5 times over nontargeted viruses. Epithelial cell adhesion molecule and integrin targeting was inferior to EGF-R targeting with a maximal increase in transgene expression of 2 times for epithelial cell adhesion molecule in 5637cells and 1.6 times for integrin targeting in T24 cells. Comparison of the wild-type replication competent virus with conditionally replicating adenoviruses (Ad5-d55K and Ad5-d24) showed superior oncolytic activity for the latter 2 in all lines. Furthermore, improved cytotoxicity (29% to 33%) was obtained in 4 of the 7 lines after pre-incubation of Ad5-d24 with 425-s11. CONCLUSIONS: EGF-R directed bispecific single chain antibodies enhance adenovirus mediated transgene expression and oncolysis in bladder cancer lines.     

Effective treatment of pancreatic tumors with two multimutated herpes simplex oncolytic viruses

Pancreatic cancer is an aggressive, rapidly fatal disease against which current nonsurgical therapy has minimal impact. This study evaluates the efficacy of two novel, replication-competent, multimutated herpes viruses (G207 and NV1020) in an experimental model of pancreatic cancer. Four human pancreatic carcinoma cell lines were exposed to G207 or NV1020, and cell survival and viral progeny production were determined. Flank tumors in athymic mice were subjected to single or multiple injections of 1 X 10⁷ G207 or NV1020, and tumor volume was evaluated over time. For all of the cell lines, G207 and NV1020 produced infection, viral replication, and cell lysis (P <0.05). NV1020 resulted in a higher production of viral progeny compared to G207. The efficacy of viral tumor cell kill was greatest in those cells with the shortest in vitro doubling time. For flank tumors derived from hs766t, single or multiple injections of both viruses were equally effective and significantly reduced flank tumor burden (P <0.05). Complete hs766t flank tumor eradication was achieved in 25% (5 of 20) of animals treated with G207 and 40% (8 of 20) of animals treated with NV1020. In vivo efficacy correlated with in vivo tumor doubling time. There were no adverse effects related to viral administration observed in any animal. NV1020 and G2O7 effectively infect and kill human pancreatic cancer cells in vitro and in vivo. Given the lack of effective nonoperative treatments for pancreatic cancer, oncolytic herpes viruses should be considered for clinical evaluation. Presented in part at the Forty-First Annual Meeting of The Society for Surgery of the Alimentary Tract, San Diego, Calif., May 21–24, 2000.     

Oncolytic herpes viral therapy is effective in the treatment of hepatocellular carcinoma cell lines

The rising incidence of hepatocellular carcinoma (HCC) in western countries, along with the poor prognosis offered by present-day treatment modalities, makes novel therapies for this disease necessary. Oncolytic herpes simplex viruses (HSV) are replication-competent viruses that are highly effective in the treatment of a wide variety of experimental models of human malignancies. This study seeks to investigate the effectiveness of oncolytic herpes viruses in the treatment of primary HCC cell lines. Sixteen commercially available human HCC cell lines were studied. G207 is an attenuated, replication-competent, oncolytic HSV engineered to selectively replicate within cancer cells. Cell lines were tested for viral sensitivity to G207 and their ability to support viral replication using standard cytotoxicity and viral replication assays. Eleven of 16 cell lines were moderately to highly sensitive to G207 viral oncolysis. HCC cell lines additionally demonstrated the ability to support viral replication in vitro with as high as 800-fold amplification of the administered viral dose observed. G207 is cytotoxic to, and efficiently replicates within, HCC cell lines in vitro. From these data, we suggest that oncolytic HSV therapy may have a role in the treatment of HCC, and in vivo studies are warranted. Presented in part at the 2005 American Hepato-Pancreato-Biliary Association Congress, Hollywood, Florida, April 14–17, 2005. Supported by grants R01CA75461 and R01CA72632 from the National Institutes of Health, and by grant MBC-99366 from the American Cancer Society (Yuman Fong).     

Effects of sequential intravesical administration of mitomycin C and bacillus Calmette-Guérin on the immune response in the guinea pig bladder

It has been suggested that intravesical treatment with mitomycin C (MMC) before instillation of bacillus Calmette-Guérin (BCG) improves the antitumor activity of BCG in human bladder cancer. Therefore, we studied the immunological effects of sequential intravesical treatment with MMC and BCG in the guinea pig. Four weekly intravesical instillations with MMC preceded six weekly intravesical BCG instillations. The delayed-type hypersensitivity (DTH) skin reaction evoked by tuberculin purified protein derivative (PPD) in guinea pigs receiving BCG intravesically appeared slightly earlier in animals pretreated intravesically with MMC than in phosphatebuffered saline (PBS)-pretreated animals. However, after completing BCG instillations no differences in DTH reaction were observed between these treatment groups. The extent of the local inflammatory reaction in the bladder wall, as well as the parameters measured in the draining iliacal lymph nodes (i.e., the weight, the number of leukocytes, and the composition of leukocyte, subpopulations), did not differ in animals treated with GCG alone or in combination with MMC. A slight increase in the MHC class II expression on the bladeer urothelium was shown if MMC and BCG treatment was combined. The adherence of mycobacteria to the bladder wall, measured using ³H-labeled mycobacteria, dit not differ between MMC/BCG-and BCG-treated animals. We conclude that MMC does not enhance the immune response against mycobacteria. Therefore, we hypothesize that a possible increased antitumor activity by the combination of MMC and BCG might be due to separate, rather than synergistic, effects of the drugs, namely a cytostatic effect of MMC on tumor cells and a local immune response in the bladder evoked by BCG.     

不同个体膀胱癌组织培养化疗药物敏感性的研究

目的：探讨不同个体膀胱癌对化疗药物的敏感性。方法：采用组织培养药敏测试法，对37例膀胱癌的化疗药物敏感性进行检测。结果：不同化疗药物对不同个体膀胱癌的抑制率差异明显。膀胱癌THP加MMC的敏感率(81．8％)和平均抑制率(67．6％)均高于任何一种单一药物；复发膀胱癌的药物敏感率和平均抑制率均低于初发者；膀胱癌的药物敏感性与分级无关。结论：不同个体膀胱癌对不同化疗药物的敏感性差异明显，复发膀胱癌对化疗药物存在一定的耐受，联合用药可以提高化疗效果。组织培养药敏测试法可有效地为不同个体膀胱癌选择最佳的化疗方案。     

YB-1-basierte Virotherapie

Therapeutic intervention using oncolytic viruses is called virotherapy. This type of virus is defined by the ability to replicate in tumor cells only and to destroy these cells upon replication. In addition, this virus type is able to induce a tumor-directed immune response. Early clinical trials have confirmed the safety profile of oncolytic viruses. Currently, different groups are working on the development of oncolytic viruses with a focus on treatment of nonmuscle invasive bladder cancer (NMIBC). A preliminary active recruiting clinical phase II/III trial ongoing in patients with a NMIBC was recently implemented in the United States. Our research group developed an oncolytic adenovirus that will soon enter a clinical phase I trial in patients diagnosed with glioma. This virus is being further modified for the treatment of NMIBC. In this review article, recent developments in the design and use of virotherapy in bladder cancer are summarized.     

表浅性膀胱癌灌注化疗的个体化研究

目的 :探讨对表浅性膀胱癌制定个体化膀胱灌注化疗方案的临床意义。方法 :对 48例表浅性膀胱癌标本行原代细胞培养及药物敏感试验 (药敏 ) ,患者随机分为两组 ,一组用丝裂霉素C(MMC)灌注 ,另一组根据药敏结果 ,选择敏感的化疗药物 ,平均随访时间 1 2个月。结果 :各化疗药物的平均抑瘤率 ,原发组分别为吡柔比星 (THP) 50 .0 %、阿霉素 (ADM ) 53 .1 % ,MMC 56 .2 %、米托蒽醌 (MH) 4 7.0 % ,复发组为THP 38.0 %、ADM43 .8% ,MMC 43 .8%、MH 31 .0 % ,组内各化疗药物抑瘤率差异无显著性意义 ,而原发组抑瘤率显著高于复发组 (P <0 .0 5) ;MMC灌注组无瘤率为 58.3 % ,药敏组无瘤率为 79.1 % ,差异有显著性意义 (P <0 .0 5)。结论 :应根据药敏结果 ,选择相对敏感的化疗药物 ,制订个体化膀胱灌注化疗方案 ,以提高疗效 ,减少肿瘤复发率     

紫杉醇及其联合化疗对表浅性膀胱癌化疗敏感性的实验研究

目的探讨紫杉醇及其联合化疗对表浅性膀胱癌的应用前景。方法自１９９５年７月～１９９７年１０月采用肿瘤细胞原代培养技术和ＭＴＴ比色法测定了３０例不同个体膀胱癌细胞及膀胱癌ＥＪ细胞系的化疗敏感性。结果紫杉醇对不同个体的膀胱癌细胞的总敏感率为１６．７％,阿霉素和丝裂霉素分别为１６．７％和２６．７％,三者间差异无显著性,但优于顺铂和噻口替哌;紫杉醇与顺铂或丝裂霉素联合后的协同性最佳,总敏感率均为８３．３％;膀胱癌细胞系的抑制率与不同个体膀胱癌细胞对相同化疗方案的抑制率差异很大。结论紫杉醇联合顺铂或丝裂霉素是可选择的灌注治疗方案;临床上应针对不同病人选择最敏感化疗方案;膀胱癌细胞系的化疗药物敏感性不能代表不同个体膀胱癌细胞的敏感性。     

Effects of photodynamic therapy in combination with intravesical drugs in a murine bladder tumor model.

This study was designed to evaluate the interaction of photodynamic therapy (PDT) and intravesical drugs (thiotepa, adriamycin, mitomycin C and BCG) in a murine transitional cell carcinoma (MBT-2) model. C3H/He mice with implanted MBT-2 flank tumors were treated with either thiotepa (TT), adriamycin (ADM), mitomycin C, Bacillus Calmette-Guerin (BCG), photodynamic therapy (PDT) or a combination of the drug and PDT. The MBT-2 tumor showed sensitivity to adriamycin, MMC or PDT compared to control. PDT combined with either adriamycin, MMC or BCG, produced a greater retardation in the growth of the MBT-2 tumor than monotherapy with adriamycin, MMC, BCG or PDT. PDT combined with the anticancer agents currently used in intravesical therapy for bladder cancer is well tolerated. The combination of PDT and intravesical drugs may enhance the tumoricidal effect of either treatment used alone.     

Application of targeted radiotherapy/gene therapy to bladder cancer cell lines

OBJECTIVES: A targeted radiotherapy/gene therapy strategy for transitional cell carcinoma of bladder is described, using [131I]meta-iodobenzylguanidine ([131I]MIBG), a radionuclide combined with a tumour-seeking drug. The aim is to decrease side effects from radiation toxicity, while increasing radiation dose to tumour. This tumour cell kill approach is augmented by radiological bystander effects. METHODS: The bladder cancer cell line EJ138 was transfected with a gene encoding the noradrenaline transporter (NAT) under the control of tumour-specific telomerase promoters. Resulting uptake of [131I]MIBG was assessed by gamma-counting of cell lysates, and NAT transgene expression by real-time RT-PCR. Cell kill of monolayers and disaggregated spheroids, dosed with [131I]MIBG, was assessed by clonogenic assay. RESULTS: NAT gene transfected cells exhibited a significantly increased active uptake of [131I]MIBG, leading to dose-dependent cell kill. Clonogenic assay of disaggregated spheroids, a three-dimensional model, suggested cell kill via bystander effects. CONCLUSIONS: Expression of a functional NAT after in vitro transfection of bladder cancer cells with the NAT gene under the control of telomerase promoters leads to active uptake of [131I]MIBG and dose-dependent cell kill. This strategy could produce a promising new treatment option for bladder cancer.     

Local chemotherapy of bladder carcinoma with mitomycin (author's transl)

40 patients with transitional cell carcinoma of the bladder, stage Tis, Ta und Tl, were treated by a topical cytostatica-therapy with Mitomycin C (MMC) after transurethral resection of the bladder in order to investigate: 1. The curative influence on the carcinoma in situ, 2. the prevention of tumor cell implantations. After an average observation time of up to the 23.4 months this concept of therapy seems to be promising because of clearly reduced recurrence rate and the lack of systemic toxicity. MMC absorption studies with 19 patients, partly with reflux and TUR-caused perforation of the bladder, showed that MMC instillation therapy (20 mg MMC in 40 ml NaCl) immediately after resection does not result inn systemically toxic serum concentration.     

Virally-directed fluorescent imaging (VFI) can facilitate endoscopic staging

Background Replication-competent, tumor specific herpes simplex virus NV1066 expresses green fluorescent protein (GFP) in infected cancer cells. We sought to determine the feasibility of GFP-guided imaging technology in the intraoperative detection of small tumor nodules. Methods Human cancer cell lines were infected with NV1066 at multiplicities of infection of 0.01, 0.1 and 1. Cancer cell specific infectivity, vector spread and GFP signal intensity were measured by flow cytometry and time-lapse digital imaging (in vitro); and by use of a stereomicroscope and endoscope equipped with a fluorescent filter (in vivo). Results NV1066 infected all cancer cell lines and expressed GFP at all MOIs. GFP signal was significantly higher than the autofluorescence of normal cells. One single dose of NV1066 spread within and across body cavities and selectively infected tumor nodules sparing normal tissue. Tumor nodules undetectable by conventional thoracoscopy and laparoscopy were identified by GFP fluorescence. Conclusion Virally-directed fluorescent imaging (VFI) is a real-time novel molecular imaging technology that has the potential to enhance the intraoperative detection of endoluminal or endocavitary tumor nodules. R. Huq: Molecular Cytology Core Facility Presented at the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) meeting, Fort Lauderdale, FL, USA, 13–16 April 2005