It has been theorized that Malignant Mesothelioma may be a good target for gene therapy because the thin mesothelial layer offers a large surface area for gene transfer, with the pleural space easily accessible for biopsy. A recent article in Current Treatment Options in Oncology by University of Pennsylvania researchers described novel approaches to gene therapy offering new hope to those suffering from this dreaded disease.
How Mesothelioma Grows
In their review of gene therapy clinical trials, the authors reported some ” limited evidence of efficacy ” for this treatment. Mesothelioma occurs when proteins allow cells to grow in an uncontrolled manner. A specific protein called mesothelin was found by researchers looking for differential expression of proteins between normal cells and mesothelioma cells. The increased presence of mesothelin on certain cells is thought to enable their growth, leading to mesothelioma.
Promising New Approaches
Previous laboratory research has shown that certain immune system cells, called T cells, can kill tumor cells that express mesothelin. In addition, both animals and human studies have shown that antibodies directed against mesothelin protein can shrink tumors. As a result, much of the mesothelioma research currently underway is focused on developing therapies that can directly block mesothelin function. One especially promising new area in gene therapy is the use of lentiviral or retroviral vectors to “transduce T-cells with modified T-cell receptors engineered to attack specific tumor antigens”. This approach has shown some success in treating other cancers.
The authors conclude “At this point in time, gene therapy for mesothelioma remains experimental and limited to a few referral centers. However, the practicing clinician can participate in moving this approach forward by not taking a nihilistic approach to MPM, but by discussing option of participating in clinical trials with his patients”.
For more information contact the University of Pennsylvania Gene Therapy Program.