A landmark discovery about the genetic make-up of tumors means scientists believe they have now found a way to get the human immune system to recognize cancer as an enemy and attack it.
A team of scientists at University College London (UCL) has found that as tumors develop, they carry "flags" on their cell surface that can be recognized by specialized cells in the immune system.
As cancer tumors grow, they evolve and mutate into groups of very different cells that often look and behave differently, which makes them hard to attack. But the study found that even after that evolution process, all cells within the tumor contain markers of their original state which can act as flags.
The specialized immune system cells, known as T-cells, will attack if they locate the flags, but they are often shielded by cancer defenses or hidden because tumors change and mutate so much. When the T-cells do find them, the cancer cells are usually able to outnumber or overpower them, especially in the advanced stages of the disease when people's immune systems are suppressed.
However now that scientists know that every cell within a tumor contains a flag, they believe there are two new potential ways to successfully treat cancer.
In the first method, scientists could use the flags on the tumor to develop a vaccine made up of the cancer flags, that would train the immune system to spot and attack them.
The second method involves harvesting T-cells that react most strongly to the cancer cells from the body, growing them in a lab and injecting the multiplied load back into the patient.
'If this doesn't work I'll probably hang my hat up and do something else'
"This is exciting... Now we can prioritize and target tumor antigens that are present in every cell, the Achilles heel of these highly complex cancers," said Professor Charles Swanton, a leader of the study from the Francis Crick Institute and UCL's Cancer Institute, in a statement.
"I will be disappointed if we haven't treated a patient within two years. Do we think it's going to work? I hope this is going to result in improvements in survival outcomes. If this doesn't work I'll probably hang my hat up and do something else," Swanton said.
Dr. Sergio Quezada, co-author of the study, said: "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 recognize on cancerous cells. Based on these new findings, we will be able to tell the immune system how to specifically recognize and attack tumors."
Quezada described the body's immune system as like a police force trying to tackle criminals. "Genetically diverse tumors are like a gang of hoodlums involved in different crimes — from robbery to smuggling," he said. "And the immune system struggles to keep on top of the cancer — just as it's difficult for police when there's so much going on.
"Our research shows that instead of aimlessly chasing crimes in different neighborhoods, we can give the police the information they need to get to the kingpin at the root of all organized crime — or the weak spot in a patient's tumor — to wipe out the problem for good."
Professor Peter Johnson, Cancer Research UK's chief clinician, said the discovery gave hope of developing better treatment for some of the trickiest cancers.
Scientists plan to develop the research into clinical trials, hoping to be able to test it on patients within two years.
Any future treatment using these methods would be extremely expensive, because it would be bespoke. It would likely take more than a year to develop the treatment for each individual patient. And it may not even work. Existing immunotherapy treatments which train immune system cells to attack cancer have had some great success, but don't work on all cancers or all patients.
The treatment is most likely to work on cancers that have a lot of mutations, however, such as melanoma and smoking-related lung cancer, reported the Guardian.
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