Faculty Bibliography

Malignant pleural mesothelioma (MPM) is an aggressive cancer, with survival of less than one year following diagnosis and treatment with current protocols. Recent studies have demonstrated the presence of the simian virus 40 (SV40)-like, large tumor antigen (Tag) in nearly 60% of MPMs. SV40 Tag is a viral-encoded tumor-specific antigen, and thus a potential target for the induction of anti-tumor immunity and the development of therapeutic vaccines. We describe here evidence for the existence of SV40 Tag-specific immune responses in patients with MPM whose tumors express Tag. Humoral immunity was demonstrated by the detection of IgG titers against Tag in serum samples from 1/3 of patients examined. CTLs were generated from the peripheral blood of an HLA-A2(+) MPM patient with a synthetic peptide representing an HLA-A2 binding epitope in SV40 Tag. The CTLs demonstrated epitope fine specificity, in that other peptides from SV40 Tag and a peptide from influenza virus were not recognized in the context of HLA-A2. Moreover, the CTLs were capable of recognizing mesothelioma tumor cells that expressed SV40 Tag, in an MHC class I restricted manner

Imaging plays an essential role in the diagnosis, staging, and follow-up of patients with malignant pleural mesothelioma (MPM). The diagnosis is often suggested by a unilateral pleural mass with a moderate to large pleural effusion seen on chest radiographs, but computerized tomography (CT) is the most frequently used technique for evaluation of the lungs in patients with MPM. CT not only suggests pulmonary metastases typically manifested as nodules or masses, but also can demonstrate underlying lung disease often caused by prior asbestos exposure. Magnetic resonance (MR) imaging may be helpful in selected patients with potentially resectable disease to further examine the local extent of tumor. Imaging with positron emission tomography (PET) using the radionuclide imaging agent (18)F fluoro-deoxyglucose (FDG) takes advantage of a basic property of tumor cells, increased glucose metabolism to identify malignant lesions. PET provides not only anatomic information, especially regarding mediastinal node metastasis, but also biochemical information about the lesion. These imaging modalities help triage patients to the most appropriate diagnostic and treatment options. Following patients after therapy usually relies on chest radiographs, although CT can more accurately describe response to therapy. This review will focus on radiologic evaluation in diagnosing, staging, and follow-up patients with MPM

Metastasis development is a complex series of events involving the generation of new blood vessels, growth, invasion with breakdown of the host matrix, transport to other sites with adhesion, and subsequent invasion of the organ that hosts the metastasis. It is only recently that the molecular basis for these events has been studied, and the understanding of this process is now leading to the development of therapies that targets one or more of the components of this series of events

Malignant pleural mesothelioma (MPM) is a uniformly fatal disease that has been recalcitrant to curative therapies. Median survivals of 8-18 months have, for the most part, led to a sense of frustration and nihilism in the medical and surgical community with regard to management of the disease, and the relatively small numbers of patients with mesothelioma have made it an orphan among other cancers with regard to research efforts and funding. This review will comment on the clinical presentation of the disease and therapeutic options that are available at this time. The role, timing, degree, and availability of cytoreductive surgery in the context of a multimodality approach for MPM will be highlighted, and various strategies that incorporate adjunctive therapies before, during, or after the operation will be discussed. Newer cytotoxic chemotherapies, either alone or in combination, are reviewed, with an emphasis on the increasing number of options with increased response rates that are becoming available for MPM patients. The results of protocols at selected centers that offer gene therapy, photodynamic therapy, hyperthermic chemotherapeutic perfusion, and intrapleural chemokines will be discussed, as well as newer preclinical approaches that base targeted therapies on novel molecular findings. In considering the newest approaches to the disease, one is encouraged to seek specialty consultation at centers that concentrate programmatic efforts on mesothelioma in order to design translational-based approaches on preclinical findings. By using such an approach, the patient and physician will find that there are considerably more options in the new century for mesothelioma

Aberrant promoter methylation and resultant silencing of several genes plays an important role in the pathogenesis of many tumor types. We compared the methylation profile of 66 malignant mesotheliomas (MMs) and 40 lung adenocarcinomas using methylation-specific PCR for seven genes frequently methylated in lung cancer. We also compared the methylation frequencies of these genes as well as the methylation index, a reflection of all of the gene frequencies, with the presence of SV40 large T-antigen (Tag) sequences, histological subtype, and patient survival. Our major findings are: (a) with the exception of the RASSF1A promoter of the RASSF1 gene, frequencies of aberrant methylation were significantly lower in MMs than in adenocarcinomas; (b) the frequency of RASSF1A aberrant methylation and the value of the methylation index were significantly higher in SV40 sequence positive MM than in negative MM; and (c) the methylation index was higher in epithelial MM than in sarcomatous/mixed MM. Our results demonstrate a relationship between SV40 and aberrant methylation in MMs

Lung cancer therapy in the future will be guided by specific characteristics of the individual tumor specimens. The molecular cancer phenotyping will allow for targeted approaches based on the amplification of oncogenes, lack of tumor suppressor genes, dysregulation of growth factors, and angiogenesis or matrix metalloproteinases. Specific immunotherapeutic approaches based on

The identification of SV40 as a possible cause of human cancer leads to the question of whether the unique properties of the virus can be exploited to treat patients with SV40-positive mesotheliomas, which are otherwise refractory to successful intervention. A modified SV40 T antigen, from which the transforming domains have been removed, has been cloned into a vaccinia virus vector and tested in animal tumor model systems. It has been shown to be effective against both subsequent tumor challenge and pre-existing tumors. Thus, the potential exists for use of such a vaccine in mesothelioma patients