Despite the continuing efforts of researchers around the world, there is currently no standardized cure formesothelioma. The asbestos-linked cancer is fast-growing and often resistant to conventional therapies. But a growing number of studies have pointed to the value of unconventional treatments like immunotherapy for mesothelioma.
Immunotherapy refers to any treatment protocol which aims to harness the body’s own immune system to fight cancer cells. In a recent article in The Lancet Oncology, two National Cancer Institute researchers summarized some of the most promising immunotherapy approaches now being investigated for mesothelioma:
In dendritic cell-based immunotherapy, dendritic cells are harvested from the patient. Outside the body, these cells are stimulated to activate a cytotoxic response against cancer cells. When they are returned to the body – usually by attaching them to an inactivated virus – the dendritic cells stimulate an immune response against tumor cells (such as mesothelioma) that produce a particular kind of antigen. The cancer vaccine Provenge is an example of dendritic cell-based immunotherapy.
Listera-based cancer vaccines use a live bacterium (Listeria) to carry tumor-specific antigens into cells. The Listeria virus produces certain chemicals that allow it to escape detection in the body until it is inside the target cells, making in a good vector for delivering anti-cancer antigens.
Other vaccines being tested against mesothelioma include allogeneic tumor cell vaccines, which use specially treated cells removed from the mesothelioma tumor itself and returned to the patient and WT1 analogue peptide vaccines. WT1 analogue peptide vaccines seek out certain chemicals that are overexpressed in cancer cells and have been shown to induce T cell immune responses in patients with mesothelioma and non-small cell lung cancer.
Because certain types of immunotherapy work best at different stages of the disease the article’s authors warn physicians that it is crucial to select mesothelioma patients carefully and to know their disease stage before considering immunotherapy. Understanding the association between the immune system’s response and how it affects the patient (clinical response) are cited as “major challenges” in the development of immunotherapy for mesothelioma. Nonetheless, immunotherapy offers a promising, more targeted and less toxic therapy for mesothelioma.
Krug, Lee, “WT1 peptide vaccinations induce CD4 and CD8 T cell immune responses in patients with mesothelioma and non-small cell lung cancer”, Cancer Immunology, Immunotherapy, Valume 59, Number 10 (2010), pp. 1467-1479.