T cells are widely known as being crucial in the fight against cancer within the body but little was known, previously, about what happened after their role was after infiltrating a tumour. In new research emerging from the Garvan Institute, the researchers were able to track the immune cells through the body after they had interacted with tumour cells to trace the T cells’ movements.

The researchers used ‘photoconversion’ to trace the movement of T cells by adding fluorescent compounds, where only cells that passed through tumour cells appeared as red while surrounding cells appeared green.

The findings found that T cells, particularly those associated with tumour destruction, were more likely exit tumour cells and, once they did, were found to travel through lymph nodes to attack other tumour sites.

This is crucial information for scientists who are looking to combat cancer once it becomes ‘metastatic’ – whereby the cancer has spread to multiple tumour sites throughout the body, which greatly reduces the patient’s chance of survival. So called ‘immunotherapies’, that harness the immune system, are becoming increasingly effective and popular in treating cancers and this may prove to be part of the puzzle to ascertain exactly why this is the case.

Lead author, Dr Tatyana Chtanova, explained what is being deduced by the findings: "What we suspect is happening is that, within the tumour, these T cells are acquiring knowledge about the cancer that helps them to seek and destroy tumour cells. It’s possible that these T cells ‘on patrol’ – which leave one tumour and move to another – are using their new-found knowledge to attack cancerous cells in the second tumour."

The study was conducted within mice and the next step for the research will be to determine whether they are able to boost the number of T cells that are able to exit tumour cells. The greater the number of T cells that exit the cells, the greater number that would then be able to travel through the body to destroy tumour cells in other locations.

Ben Hargreaves