Gene therapy is a relatively new treatment approach, though it provides great hope and promise for improving the disease’s extraordinarily poor prognosis. Because the amount of time between initial exposure to asbestos and development of mesothelioma is so extensive (between 15-40 years), the cancer is not often detected until its most advanced stage. Though there have been significant advancements in treatment and detection techniques, the disease continues to be extremely aggressive and usually fatal. Gene therapy involves replacing, removing, altering, or introducing new genes into the body’s network in order to attack cancer cells.
The modification of genetic makeup sheds new light on traditional cancer treatment. Mesothelioma lawyers are closely monitoring advancements and studies made in this field. Gene therapy is a promising development, and of major interest to doctors, researchers, and patients around the world. Malignant pleural mesothelioma accounts for about 80% of all mesothelioma cases and is directly caused by exposure to asbestos. Asbestos was used primarily in construction, shipbuilding, automotive, and friction product manufacturing throughout the twentieth century. Mining ceased in the United States in 2002, though it is still imported annually. Unfortunately, median survival for mesothelioma is between 6 and 18 months. Fortunately, the disease is an excellent target for gene therapy because the thin layer of mesothelial and malignant cells offers a large surface area for efficient, rapid, and diffuse gene transfer.
A recent article by the National Institute of Health reviewed the clinical experience in gene therapy for mesothelioma and the future directions of this approach. Gene delivery efficiency is an important requirement for successful gene therapy.
Tumor suppressor genes may undergo loss of function by a variety of mechanisms including mutation, deletion, methylation, or a combination of these. The rationale for this approach is to use a gene therapy vector to encode a tumor-suppressor gene that is mutated or absent in the majority of lung cancers. Theoretically, replacement of a non-functional copy of a tumor suppressor gene could lead to suppression of tumor growth or tumor cell death.
Immunotherapy is based on the premise that there are intrinsic differences in the protein composition of tumor cells that allow the immune system to recognize tumor cells as “foreign” and kill them. However, established tumors have evolved many ways to evade or overwhelm the immune system and thus some sort of exogenous stimulus is needed to enable the immune system to effectively eliminate tumor cells. Gene therapy approaches are becoming increasingly important in implementing immunotherapy. Specifically, gene therapy has been used to introduce tumor antigens directly, to introduce tumor antigens into branched cells, to modify tumor cells used as vaccines, and to introduce tumor-specificity to T cells.
Numerous other strategies have been employed in the cancer gene therapy and in some of these trials patients with lung cancer have been included in either Phase I or II studies.
Gene therapy studies in malignant pleural mesothelioma has been facilitated by the fact the pleural space is easily accessible and amendable to biopsy allowing delivery of study gene and fluid sampling to confirm successful gene transfer. Access and assessment of the pleural space have also been enhanced by the availability of tunneled pleural catheter systems. Accordingly, several groups have used a variety of gene therapy approaches in an attempt to improve treatment of these diseases.
Suicide gene therapy involves transduction of tumor cells with a gene encoding for a specific enzyme that induces sensitivity to an otherwise benign agent. An advantage of suicide gene therapy is the induction of the killing of neighboring cells.
In general, these trials have shown safety, but only intermittent efficacy.
In vivo gene transfer has been clearly achievable, but with the vectors
currently available, it has been very difficult to transduce more than
a small percentage of tumor cells, and this is usually only accomplished
by local injection.
However, the primary direction of the field has been a shift toward ‘immuno-gene therapy.’ This strategy requires only enough gene transduction to stimulate an immune response. Promising approaches involve using gene therapy to stimulate anti-tumor responses by a vaccine.
Gene therapy for lung cancer and mesothelioma has not yet reached clinical practice. Despite what some perceive as a slow start, we feel that progress in clearly being made and this therapeutic took will find its place in the anti-cancer collection in the next decade.
If you were exposed to asbestos and developed a related illness, such as mesothelioma, you may be eligible to compensation. Contact an asbestos exposure attorney immediately for a free legal consultation.