Scientists are reporting a breakthrough in cancer research that could lead to the development of highly targeted immunotherapies that enable the body to fight the disease without harming healthy tissues.

Researchers funded by Cancer Research UK and the Rosetrees Trust have made a “groundbreaking discovery” in understanding how the genetic makeup of tumours can be recognised and exploited by the immune system, even when the disease is at its most advanced stages.

As cancerous tumours develop, their various genetic faults can be flagged on the cancer cell surface, with unique mutations appearing in different parts of the tumour. The researchers found that some of these antigens represent the very earliest mutations of the disease and are thus displayed on all cells in the tumour, rather than just a subset. 

This finding opens the door to the development of therapies that specifically activate T cells to target all tumour cells at the same time, based on the disease’s own genetic signature. In future, scientists could exploit this by developing a therapeutic vaccine to activate T-cells, or harvesting, growing and administering T-cells back into the patient that recognise the antigens common to every cancer cell, CR UK said.

Study co-author Professor Charles Swanton from the UCL Cancer Institute and a Francis Crick Institute, said the findings are exciting: “There was evidence that complex tumours with many mutations could increase the chance of the immune system spotting them; now we can prioritise and target tumour antigens that are present in every cell, the Achilles heel of these highly complex cancers”.

“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. This is really fascinating, and takes personalised medicine to its absolute limit where each patient would have a unique, bespoke treatment.”

“As well as suggesting a new way to treat cancer, the research fills key gaps in our knowledge about the effects of the immune system on tumours,” Professor Peter Johnson, Cancer Research UK's chief clinician. “This gives us hope of developing better treatments for some of the cancers we have previously found hardest to treat.”

The research was published in the journal Science.