StemCell Therapy

TOKYO Lurking deep inside some tumours are "factories" full of immune cells that help the body fight a rearguard action against cancer and are key to helping some patients recover, new research has shown.

In recent years, doctors have turned to a new treatment for cancer - immunotherapy - that works by leveraging the body's immune system to fight tumours.

The technique has largely focused on white blood cells called T-cells, which are "trained" to recognise and attack cancer cells.

But the innovative treatment works well for only around 20 per cent of patients, so researchers have been trying to understand why some people respond better than others.

Three papers published last Thursday in the journal Nature point the way, identifying a key formation inside some tumours: tertiary lymphoid structures (TLS).

TLS function like factories or schools for immune cells that help the body fight cancer, said Professor Wolf Fridman, a professor emeritus of immunology at the Cordeliers Research Centre of the Paris Descartes University medical school, who led one of the studies.

He said the cells need to be educated in "schools" - the TLS - where they learn to recognise and attack cancer cells.

Key to the findings is that T-cells are far from the only immune cells capable of taking the fight to cancer. Researchers found the TLS were full of B-cells, a kind of immune cell that produces antibodies.

"We have been T-cell addicts for 15 years in cancer," Prof Fridman said. "We analysed these sarcomas to see what groups they had and what's striking is that these B-cells appeared."

Dr Beth Helmink, a fellow in surgical oncology at the University of Texas' MD Anderson Cancer Centre, who worked on a second study, said the research had changed perceptions of the role of B-cells in immunotherapy.

"Through these studies, we find that B-cells are not just innocent bystanders, but are themselves contributing in a meaningful way to the anti-tumour immune response," she said in a statement from the centre.

The discovery is a surprise, as an abundance of B-cells in cancer patients has sometimes been seen as a marker for poor prognosis.

But the studies found patients with high levels of B-cells inside TLS in their tumours were more likely to respond well to immunotherapy.

Dr Louisa James, a lecturer in immunology at Barts and the London School of Medicine and Dentistry, Queen Mary University of London, said: "This series of studies is exciting because (it represents) real progress in the treatment of different types of cancer."

Dr James, who was not involved in the studies, added: "In the short term, these results provide a new tool to help predict which patients are likely to benefit from treatment with immunotherapy and may also pave the way for improved treatments in the future."

There are still many unanswered questions, including why TLS form in some tumours and not others.

While it now seems clear that B-cells inside the structures play a key role in the success of immunotherapy, scientists are not sure precisely how.

It may be that the B-cells are on the front lines, producing antibodies that attack cancer cells efficiently - or they may be bolstering T-cells, or perhaps even doing both.

And not all TLS are created equal: The researchers found three categories, but only one type was "mature" enough to churn out cancer-fighting immune cells.

The research opens up promising new avenues, the authors said.

Initially, the findings could help doctors screen patients to see which of them are most likely to respond well to immunotherapy.

It could eventually mean more patients are successfully treated with the technique, said Professor Goran Jonsson, a professor of oncology and pathology at Lund University in Sweden, who worked on a third study.

"If we come up with a treatment that could enhance TLS formation, we could combine this with current immunotherapy regimens," he said. "Most likely, this would lead to more patients responding to immunotherapy."

AGENCE FRANCE-PRESSE

Read more here:
Scientists find immune cells that fight tumours from within - The Straits Times

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