Scientists find immune cells that fight tumors from within

In recent years, doctors have resorted to a new treatment for cancer, immunotherapy, which works by harnessing the body’s immune system to fight tumors.

TOKYO: Lurking inside some tumors are “factories” full of immune cells that help the body fight a rearguard action against cancer and are key to helping some patients recover, according to new research.

In recent years, doctors have resorted to a new treatment for cancer, immunotherapy, which works by harnessing the body’s immune system to fight tumors.

The technique has focused primarily on white blood cells called T cells, which are “trained” to recognize and attack cancer cells.

But the innovative treatment only works well for about 20 percent of patients, and researchers have been trying to understand why some people respond better than others.

Three articles published Thursday in the journal Nature point the way, identifying a key formation within some tumors: tertiary lymphoid structures (TLS).

These structures function as “factories or schools” for immune cells that help the body fight cancer, said Wolf Fridman, professor emeritus of immunology at the University of Paris at the Cordeliers Research Center, who helped lead one of the studies.

“Cells need to be educated in schools, which are tertiary lymphoid structures,” where they effectively learn to recognize and attack cancer cells, Fridman told AFP.

No ‘innocent bystanders’

The key to the findings is that T cells are far from being the only immune cells capable of fighting cancer, and researchers discovered that TLS was full of B cells, a type of immune cell that produces antibodies.

“We’ve been addicted to T cells for 15 years in cancer,” Fridman said with a laugh.

“We analyzed these sarcomas to see what groups they had and the surprising thing is that these B cells appeared.”

Beth Helmink, a member of surgical oncology at the MD Anderson Cancer Center at the University of Texas who worked on a second study, said the research changed perceptions of the role of B cells in immunotherapy.

“Through these studies, we found that B cells are not only innocent bystanders, but are also contributing significantly to the antitumor immune response,” he said in a statement issued by the Center.

The discovery is somewhat surprising, since the abundance of B cells in cancer patients has sometimes been seen as a marker of poor prognosis.

But studies found that patients with high levels of B cells within TLS in their tumors were more likely to respond well to immunotherapy.

“These three studies provide interesting data that show that … B cells that produce antibodies significantly influence the ability of patients with certain types of cancer to respond to immunotherapy,” said Lawrence Young, director of the Cancer Research Center from the University of Warwick, which did not participate in the studies.

The work “could be used to improve the effectiveness of cancer immunotherapy for all patients,” he said.

Improving cancer treatment

There are still many unanswered questions.

Scientists are still unsure why structures form in some tumors and not in others.

And although it now seems clear that B cells within the structures play a key role in the success of immunotherapy, scientists are not sure how.

It may be that B cells are on the front line, producing antibodies that attack cancer cells efficiently.

Or they may be reinforcing the T cells, or maybe doing both.

And not all TLS are created in the same way: the researchers found three categories, but only one type was “mature” enough to produce immune cells that fight cancer.

In the future, the research opens several promising avenues, the authors said.

Initially, it could help doctors evaluate patients to see which ones are more likely to respond well to immunotherapy.

And eventually, the research could mean that more patients could be successfully treated with the technique, said Goran Jonsson, a professor of oncology and pathology at Lund University who worked on a third study.

“If we can think of a treatment that can improve the formation of TLS, we could combine this with the current immunotherapy regimens,” he told AFP.

“Most likely, this will lead to more patients responding to immunotherapy.”

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