Cancer biologists in India have identified eight genes they say could be used to predict the spread of lung cancer to the liver through a process called metastasis and design new anti-cancer therapies.

Their study suggests that changes in these eight genes are associated with a greater risk of liver metastasis, a condition known to worsen the illness and lower the survival periods for patients.

“We’ve got a mathematical equation that combines the activity levels of each of the eight genes into a score — the higher the score the greater the chances of metastasis,” said Rakesh Rawal, professor of life sciences at Gujarat University, Ahmedabad, who led the study.

In metastasis, tumour particles break away from the primary cancer sites to other organs such as the bone, brain or liver. Lung cancer is a difficult-to-treat illness: only about 35 in 100 patients with Stage 1 lung cancer survive five years after diagnosis and about 40 per cent patients of lung cancer develop liver metastasis.

Scientists expect the search for genes involved in metastasis to provide fresh insights into the biological mechanisms that underlie the process and reveal potential molecular targets to treat cancers.

Rawal and collaborating research scholars at Gujarat University first searched dozens of previously published studies on cancer and observed that 15 genes appeared to be consistently associated with liver metastasis.

They analysed the activity levels of each of these 15 genes in 30 patients with non-metastatic lung cancer and 32 patients with metastatic lung cancer, looking for mathematical correlations linking the genes to metastasis.

Among the 15 genes, eight displayed strong associations. A mathematical algorithm, or equation, combining the expression levels of all eight genes yields scores linked to the risk of liver metastasis.

Their analysis suggests that the eight-gene test can successfully predict liver metastasis in 90 among 100 patients with lung cancer. The study was published in the journal PLOSOne on Thursday.

The researchers have said the test needs to be validated through more patients before it can be proposed as a predictive diagnostic tool.

Research associate and team member Kanisha Shah, who tried to determine the biological relevance of the eight genes, said that some of them appeared to play a role in the “transport system” that drove tumour particles from the primary site to the metastasis site.

“Tiny particles called exosomes shed by tumours are part of this transport system,” Shah said. “It is possible that the exosomes, expressing the proteins made by the eight genes, help create metastatic niches in the liver where lung cancer cells get deposited.”

The scientists say the eight genes and the biological pathways through which they drive metastasis could help design novel therapeutic strategies to treat patients of lung cancer with liver metastasis.