New breakthrough in cancer research
A new breakthrough in cancer research has discovered that even though cancer cells mutate wildly within a person's body, the cancer cells within each patient also have common mutations – ones that could be isolated and fought off by certain immune cells.
Experts are now touting that this advanced discovery could lead to a new way of treating cancer.
Researchers in England identified antigens on the surface of tumour cells that should attract immune cells to attack, but are turned off by the genetic mutations that drive the growth of cancer, according to the new study.
Cataloguing different types of antigens, which are not necessarily present in all cells within a tumour, could help the development of better immunotherapy drugs and a clearer idea of which patients will respond the best to each treatment.
According to the study, published in the journal Science, researchers said the new understanding explains why some patients with the same cancer respond differently to the drugs, and others respond greatly but later have significant relapses.
Immunotherapy targets proteins on the surface of cancer cells, encouraging and enhancing the immune system's ability to see cancer cells as a foreign invader and attack as with any other infection. The most well-known is Keytruda, which former President Jimmy Carter was successfully treated with in 2015 for melanoma on the brain.
"For many years, we have studied how the immune response to cancer is regulated without a clear understanding of what it is that immune cells recognise on cancerous cells," Dr. Sergio Quezada, a researcher at the University College London, said in a press release. "Based on these new findings, we will be able to tell the immune system how to specifically recognise and attack tumours."
The researchers analysed medical records for 139 lung cancer patients, looking at the relationship between T cell reaction to clonal neoantigens on the surface of cancer cells and patients' survival. They found that patients with higher levels of the antigens saw greater benefit from immunotherapy treatment.
Cancers that survive and grow larger tend to have fewer antigens, so the immune system does not recognise them. Getting the immune system to recognise antigens is also tricky because cancer cells continue to mutate and evolve as the tumours grow, so antigens present on one side of a tumour may not be on the other side.
"This opens up a way to look at individual patients' tumours and profile all the antigen variations to figure out the best ways for immunotherapy treatments to work, prioritising antigens present in every tumour cell and identifying the body's immune T cells that recognise them," said Dr. Charles Swanton, a scientist at the Francis Crick Institute.
"This is really fascinating, and takes personalised medicine to its absolute limit where each patient would have a unique, bespoke treatment."