Daily exposure to ozone pollution linked to higher early death risk

Scientists have developed a new method to spot melanoma cells circulating in the blood, an advance that could significantly improve the monitoring of cancer patients, and guide future treatment.

Melanoma is a type of cancer that develops from the pigment-containing cells known as melanocytes. Such cancers typically occur in the skin, but may rarely occur in the mouth, intestines, and eye. The researchers, including those from Edith Cowan University in Australia, pioneered a new technique to detect circulating tumour cells (CTCs) that could provide a new avenue for cancer diagnosis and therapies.

"These preliminary findings are a first step towards a new way to stop melanoma from spreading around the body," said Associate Professor Elin Gray from Edith Cowan University. Cancer spreads around the body when CTCs shed from the primary tumour, and travel through the blood to form secondary tumours (metastases) in other organs, the researchers explained. "If we can find a way to reliably detect these cells, then we have a chance to stop melanoma in its tracks with a powerful diagnostic tool and perhaps opportunities for therapies in the future," said Gray, lead author of the study published in the British Journal of Cancer. Until now, Melanoma CTCs have proved to be incredibly elusive, with detection rates wildly varying from 40 to 87 per cent.

"We now understand that CTC detection cannot be resolved with a one-size-fits-all approach," Gray said. The researchers, including those from the Harvard Medical School, said there is a huge amount of variety in the shape and bioactivity of these CTCs, and so they all look different and respond differently to assay tests. "To complicate things further, melanoma CTCs are hidden among thousands of other cells and matter in blood. Within one millilitre of blood, there are often fewer than 10 cancer cells among one billion red cells, and one million white blood cells," Gray explained.

"It is much like finding a needle in a haystack," she said. Armed with a better understanding of the complexity of the task, the researchers tried a multi-faceted approach to detecting melanoma CTCs. "By combining three assays together, the researchers raised detection rates to 72 per cent, which was a significantly and consistently higher result than using one test.

"We are confident this approach is a move towards the reliable detection of CTCs, but we now need to tweak the assay to include a better combination to capture the broadest range of CTCs," Gray said. The team is now working with artificial intelligence (AI) experts to fast-track the identification of CTCs.