I was positively energized to see that new innovations in cancer treatment are emerging from the laboratory and appearing at the bedside. Melanoma is a very nasty form of skin cancer, and is one ot those entities. Recent news that gene therapy has been introduced as a tool to combat this cancer is very encouraging. Scientists at the National Cancer Institute in Washington have employed gene therapy with some success. It involves a very nifty technique called adoptive cell transfer to get the patient's own immune system to attack and destroy cancer cells. The idea originated in research showing that some people actually produce cells capable of destroying cancer cells, but in small numbers.
Blood is a combination of many different blood cells. The most common are red blood cells, but also floating around are various immune guard cells called lymphocytes. The process begins by collecting a sample of blood from a patient afflicted with melanoma. The lymphocytes are then separated from the rest of the cells and exposed to a manipulated virus to allow infection.
Viruses are very small, and amount to a fraction of the size of the cell that they are invading. This is because viruses are little more than a piece of genetic material contained within a protein coat. Viruses infect and borrow the internal machinery of normal cells in order to survive and propagate.
The rotavirus that is used to infect the patient's blood cells is specail. It contains a genetic code that has been artificially modified and inserted. The code that it contains is engineered to produce a receptor protein that will latch on to the surface of the cancer cells. The lymphocytes, taken from the patient, go on to develop the ability to recognize melanoma cells. These modified cells are then transferred back into the patient's blood stream where they circulate and attach to the cancer cells and cause them to disintegrate. It is called Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4). The cells go on to multiply.
The problem encountered with this technique is that cancer cells are very similar to normal cells and these programmed cells have trouble find all the cancer cells. They can latch on to normal cells and cause severe reactions. In this case, melanoma vaccine was administered to the engineered cells. It contained non-harmful peptides that prompted other parts of the immune system to also attack the cancer.
On the positive side, this whole process was being used in patients with advanced melanoma. It is in the midst of being refined, and potential is under development to employ with other types of cancer and provides compelling evidence to further support genetic engineering and stem cell research.
Prevention is still the best strategy. Our skin accumulates damage over the years. All those burns and tans of past years accumulate to increase your risk of various skin cancers. The UV index is a useful tool to tell you how many minutes you can enjoy in today's sunshine before it starts to damage your skin. Use of wide brim hats, lotions with sun protection factor (SPF) over 30 is highly encouraged. Despite my generation being brought up slathered in baby oil to get those sun vitamins, tanning is not a medically sanctioned activity, but getting a little sun each day is! Have a sun-safe summer.
● Melanoma from Wikipedia, the free encyclopedia.
● Gene Therapy Halts Skin Cancer by Daniel J. DeNoon, Reviewed by Louise Chang, MD, WebMD Health News.
● Q&A: Skin cancer gene therapy from BBC News.
● Killer T-Cells: The promise of using genetic engineering to treat cancer by Sydney Spiesel, Slate Magazine, a daily magazine on the Web, Washington Post, Newsweek.
● Principles of adoptive T cell cancer therapy by Carl H. June, Abramson Family Cancer Research Institute and Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA. "Adoptive T cell therapy for cancer is a form of transfusion therapy consisting of the infusion of various mature T cell subsets with the goal of eliminating a tumor and preventing its recurrence."
● Adoptive T-Cell Transfer for Metastatic Melanoma. PowerPoint presentation in PDF by James Yang, Surgery Branch, National Cancer Institute, Bethesda, MD.
● Adoptive T cell therapy for cancer in the clinic by Carl H. June. "The transfusion of lymphocytes, referred to as adoptive T cell therapy, is being tested for the treatment of cancer and chronic infections. Adoptive T cell therapy has the potential to enhance antitumor immunity, augment vaccine efficacy, and limit graft-versus-host disease."