Breathing in extra oxygen could help fight cancer, study shows

A study in mice suggests something as simple as breathing in extra oxygen might give immune cells a boost in attacking cancer.

The immune system often can spot and destroy abnormal cells before they grow into cancer. But when tumours manage to take root, they put up defences to block new immune attacks.

With the extra oxygen, "you remove the brake pedal" that cancer can put on tumour-fighting immune cells, said Michail Sitkovsky, director of the New England Inflammation and Tissue Protection Institute at Northeastern University, who led the work.

Tumours can grow so rapidly that they outpace their blood supply, creating a low-oxygen environment. The lack of oxygen in turn spurs cancer cells to produce a molecule called adenosine, which essentially puts nearby tumour fighters called T cells and natural killer cells to sleep, said pharmacologist Edwin Jackson of the University of Pittsburgh, who co-authored the study.

Sitkovsky's team wondered if just getting more oxygen to an oxygen-starved tumour could strip away the cancer's defence.

So they put mice with different kinds of lung tumours inside chambers that mimic what's called supplemental oxygen therapy. Extra oxygen changed the tumour's environment so immune cells could do their jobs, the researchers reported in .