Real-time intraoperative detection of melanoma lymph node metastases using recombinant vaccinia virus GLV-lh68 in an immunocompetent animal model

Abstract

There is a clinical need for improved intraoperative detection of lymph node metastases from malignant melanoma (MM). We aimed to investigate the use of recombinant vaccinia virus GLV-lh68, expressing green fluorescent protein (GFP), for real-time intraoperative detection of melanoma lymph node metastases in an immunocompetent animal model. Mice hearing foot pad tumors received intratuitioral injections of GLV-lh68, and 48 hr later were evaluated for popliteal lymph node metastasis using noninvasive bioluminescence imaging and fluorescence imaging. Histologic analysis of lymph nodes was performed to determine sensitivity and specilcity of virus-mediated detection, Intratumoral injection of GLV-1H68 into primary foot pad melanoma tumors resulted in viral transmission to popliteal lymph nodes, infection of lymphatic metastases, and transgene expression that was reliably and easily detected. Histologic confirmation demonstrated favorable operating characteristics of this assay (sensitivity 80%, specificity 100%, positive predictive value [PPV] 100%, negative predictive value [NPV] 91%). Detection of marker gene expression by GLV-II168 allowed the detection of lymphatic metastases in an immunocompetent animal model of MM. This assay is rapid, sensitive, speciic and easy to perform and interpret. As a candidate gene therapy virus for killing cancer, Gi V-lh68 may also have significant concomitant diagnostic utility in the staging of cancer patients. © 2008 Wiley-Liss, Inc.