Chemotherapy not the only solution for cancer, now light can be used to attack tumour cells

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The problem, however, is that immunotherapy can cause the immune system to overreact or under-react, Kim said. In addition, cancer cells are evasive and can hide from killer T-cells. Aggressive tumours also suppress the immune system in the areas surrounding the malignancy (called the microenvironment), keeping T cells out. If the immune system under-reacts, currently the only way to modify it is to pump more T cells into the body.

But that often unleashes a storm of toxicities that can shut down a patient’s organs. Kim’s laboratory focused on how to overcome the immune-suppressive environment that cancer creates. The researchers discovered that a molecule called channelrhodopsin (CatCh), which is active in algae and is light sensitive, could be introduced to the immune system via a virus and activated to control the T- cell response to cancer.

The researchers tested in mice an LED chip which could eventually be implanted in humans. The team evaluated their methods in mice with melanoma on the ears.The animals wore a tiny battery pack that sent a wireless signal to the LED chip – allowing researchers to remotely shine light on the tumour and surrounding areas, giving T cells a boost for their cancer-killing function. The optical control allowed the immune system to nearly wipe out the melanoma with no toxic side effects, the study reported.

Future studies, Kim said, would determine whether the wireless LED signal can deliver light to a tumour deep within the body instead of on the surface area, and still have the ability to stimulate T cells to attack.