A new form of cancer treatment, adoptive T cell therapy, is showing promise as described in a recent article in Science and later reported by the NYT (see: Patient’s Cells Deployed to Attack Aggressive Cancer). Here's an excerpt from the story:
Doctors have taken an important step toward a long-sought goal: harnessing a person’s own immune system to fight cancer. An article published Thursday in the journal Science describes the treatment of a 43-year-old woman with ...[cholangiocarcinoma] that had spread from her bile duct to her liver and lungs, despite chemotherapy....[The patient] learned in 2009 that she had bile-duct cancer, or cholangiocarcinoma...She had surgery to remove about two-thirds of her liver, but within a few months the disease had turned up in her lungs. She went through one grueling regimen of chemotherapy, then another.....But by last summer, the lung tumors were growing again [despite chemotherapy and T-cell infusions]. By then, the team had sequenced the genome of her cancer, and done extensive studies on her immune system. And it had found what researchers had long hoped for: a mutation in the cancer that was unique to it and not found in normal cells, and a type of [the patient's own] T cell[s] that would attack the mutation. Tests revealed that only 25 percent of the T cells that had been [previously] given to [the patient] were of this specialized type. Again, the team cultured [her] T cells, but this time it used only the ones that would go after the mutation. In October, she received more than 120 billion T cells, 95 percent of which were the highly specific ones. Her tumors quickly began shrinking, and have continued to do so for the past six months, [her physician] said.
Here's a more detailed explanation of adoptive T cell therapy (see: Adoptive T Cell Therapy):
Adoptive T cell therapy involves the isolation and ex vivo expansion of tumor specific T cells to achieve greater number of T cells than what could be obtained by vaccination alone. The tumor specific T cells are then infused into patients with cancer in an attempt to give their immune system the ability to overwhelm remaining tumor via T cells which can attack and kill cancer. There are many forms of adoptive T cell therapy being used for cancer treatment; culturing tumor infiltrating lymphocytes or TIL [tumor infiltrating lymphocytes], isolating and expanding one particular T cell or clone, and even using T cells that have been engineered to potently recognize and attack tumors.
In the case of the patient above and after previous treatment failures, her physicians did the following: (1) sequenced her tumor; (2) found a mutation of the cancer not shared by the other normal cells in her body; (3) selected a type of her own T cells that would attack the cancer cells and cultured them; (4) injected 120 billion of of these cultured cells back to her in a form of enhanced immunotherapy.
The article pointed out that this whole procedure was a laborious, expensive, and a highly customized form of immunotherapy, clearly not suited to large-scale trials. Moreover, it's likely that some malignant cells remain in her body that, being genetically highly atypical, may develop resistance to T cell therapy, and start growing anew. However, successful experiments such as these will point the way to new forms of cancer immunotherapy in which only the malignant cells are targeted and the cancer treatment does not take such a heavy toll on the patient.