It seems that a favorite plotline of crime shows is the methodical serial killer who finally slips up. Their crimes are usually horrendously vile. There's a different kind of "serial killer" that we can actually like, a biological one. Let me tell you about the newest enemy of cancer.
One of the most common forms of cancer in the U.S. is leukemia, affecting 45,000 individuals each year.[1] The usual treatment is chemotherapy, which kills the cancerous white blood cells that are circulating throughout the blood stream and lymph nodes. Chemotherapy, however, indiscriminately kills healthy tissue, and causes some fairly unpleasant and sometimes dangerous side effects. One of the key goals of cancer research is to develop treatments that target only cancer cells and leave healthy tissues alone. Help is on the way, this time from genetic engineering.
For the first time scientists have successfully used gene therapy to destroy cancer cells in three patients with advanced chronic lymphocytic leukemia.[2] In this study, some of the patients' T-cells were genetically modified to target the patient's leukemia. T-cells are a type of white blood cell involved in the immune system. The researchers designed these cells to have a "lock-in-key" mechanism so no healthy cells would be harmed. These T-cells turned into "serial killers." Not only did they "hunt down" the cancerous tumors, they "enlisted" other cells that multiplied and joined the attack on the cancer. An average two pounds of tumor was removed from each patient.[3] In one patient, over 7 pounds of tumor was completely destroyed.
For patients with this form of late-stage leukemia the only current treatment is a bone marrow transplant, which is fatal for 1 in 5 patients. Even with a transplant, the cure rate is only about 50%. Remarkably, only a month after the experimental "killer T-cell" transplant, not one patient had any sign of cancer.
Two of the three men in the study have been cancer-free for a year, while the third has had a slight recurrence of the disease. While the long-term effects of the treatment are unknown, the researchers found evidence of "memory" T-cells following the disappearance of the cancer, which they hope will give these patients ongoing protection against a recurrence of cancer.
This breakthrough is the result of over 20 years of research into the use of genetic engineering to cure cancer. Now that they have the first "proof-of-principle" that such treatment works, researchers hope to design similar therapies for breast, ovarian, lung, and skin cancers. This treatment is still at the experimental stage; it will take several years and additional studies to determine the long-term safety and efficacy.[4] While this delay may be frustrating to patients with cancer and their families, the ethical guidelines must be followed to ensure that the therapy actually works for a significant group of people, and that it does not create any unnecessary harm.
I am amazed at the wonders of modern science and medicine, the ingenuity of the researchers, and the perseverance of the patients. This kind of scientific knowledge is a good gift from God. And that's a plot line we can all celebrate.
[1] National Cancer Institute, "Leukemia," http://www.cancer.gov/cancertopics/types/leukemia (accessed October 10, 2011).
[2] Kerry Sheridan, "'Killer' T-cells Erases Form of Leukemia," Vancouver Sun, August 11, 2011 http://www.vancouversun.com/health/Killer+cells+erases+form+leukemia/5241504/story.html (accessed October 10, 2011).
[3] "Leukemia Breakthrough - Serial Killer T Cells Wipe Out Tumors in Small Trial," Medical News Today August 11, 2011, were genetically modified to target the patient's leukemia (accessed October 10, 2011).
[4] Previous clinical trials involving gene therapy have failed because patients have been harmed or have died as the result of treatment. The research group at the University of Pennsylvania plans to treat two children and 13 more adults before moving on to a larger Phase II clinical trial.