Exciting new research in the field of cancer treatment will allow doctors to target skin cancer tumors with T cells (a type of white blood cell used to fight off illness), causing the tumor to shrink and go into remission. Called “adoptive T cell therapy,” the process does not use chemotherapy or radiation treatment, making it a potentially viable and natural alternative to traditional methods of treating cancer.
The premise of the research is as simple as it is revolutionary. Ivy Lai, lead clinical research technician at Fred Hutchinson Cancer Research Center, explains. “Cancer patients have a depleted number of white cells, so our T cells are specialized to focus on cancer tumors by increasing T cell number by: 1) infusing billions of T cells onto the tumor and 2) specializing T cells to migrate to the tumor more effectively.”
The treatment begins with a procedure called leukapheresis, a process that isolates and extracts white blood cells from a sample of blood. This procedure is performed using a machine (similar to a dialysis) that separates T cells out of blood drawn from one arm, and redirects the remaining blood through another arm. After the T cells are isolated, research technicians such as Lai train the T cells to recognize a peptide sequence unique to that tumor, run the cells through a sorter to find the bulk population that kills tumor the best, and grow the cells into a dose based on the patient’s body surface mass.
The T cells are then infused into the patient, in the hopes that the cells will recognize the tumor and actively combat it.
Though the treatment is still in the research stage, Lai says that patients can sign up for clinical trials to determine the efficacy of the procedure.
Most test patients have experienced a partial shrinking of their tumors after having undergone adoptive T cell therapy. Dr. Cassian Yee, the doctor who oversees and implements the research, reports that patients display either a halt or reduction of tumors when infused by artificially developed T-cells, called CD8+, and a chemical dubbed IL-2 that causes T-cells to replicate.
Lai states that in one particular melanoma case, wherein a 52 year-old man in Oregon was infused with 5 billion of his own T cells, the melanoma was eradicated and has not returned since the man received treatment. The team at Fred Hutchinson predicts that up to 25 percent of late stage melanoma can be treated with adoptive T cell therapy, provided that the patient exhibits identical immune system traits as the test patient from Oregon.
“Most of our patients get partial responses,” says Lai. “We had one complete response, so we’re trying to figure out why that patient went into remission, and why people relapse. There’s something with his T cells that we haven’t figured out, and I think that’s the research aspect of it.”
Adoptive T cell therapy, or immunotherapy, represents a growing branch of cancer treatment that seeks to treat cancer tumors without using radiation and chemotherapy. If the research proves successful, in the sense that a large number of patients remain melanoma-free, the treatment could possibly supplement or even replace traditional forms of therapy usually associated with cancer treatment.
For now, however, the team of researchers at Fred Hutchinson must seek ways to enhance the treatment so that it can be used more efficiently. The next step involves training T cells to recognize other tumor specific proteins to give the treatment a wider range of targeting cancers.
“We just started treating our first merkel cell carcinoma (a rare and aggressive type of skin cancer) patient and he’s reacting really well,” says Lai regarding her current research. “We got rid of one of his tumors, and he has two other ones that shrunk, and we treated him twice so far. Eventually this treatment may help merkel cell patients too.”
Adoptive T cell therapy could very well reflect the future of cancer treatment, in which the body’s natural healing methods can be utilized for the benefit of the cancer patient. Hopefully, this research can be used for not just skin cancer patients, but also the broad spectrum of cancers afflicting people today.
