A pioneering technique designed to spot differences between immune cells in tumors could speed the development of cancer treatments, research suggests. Scientists say the approach could be used to help doctors choose the best treatments for individual patients and predict which tumors are likely to respond to a particular therapy.

It could help target the use of immunotherapy a new form of treatment that uses the body defenses to tackle cancer. This therapy has shown great promise in recent years, but it will be a challenge for doctors.

The new approach based on gene analysis makes it easier to spot the range of immune cells present in a tumor. These cells could help the body detect and kill cancer when activated by certain drugs, scientists say.

Cancerous and healthy cells

Traditional treatments such as radiology do not discriminate between cell types and attack both cancerous and healthy cells, often leading to side effects. Researchers at the University of Edinburgh analyzed genes from anonymized medical databases of thousands of tumors to identify genes associated with immune cells.

Este allowed them to quickly detect immune cells in a tumor based on their genetic code even when they were mixed in with harmful cancerous cells and normal cells. They say that this resource called ImSig paints the best picture of tumors to date and will allow scientists to study how certain immune cell types affect cancer growth.

In the future, this could help doctors decide which patients were most likely to respond to immunotherapy, experts say. The study is published in  Cancer Immunology Research and was funded by the Biotechnology and Biological Sciences Research Council.

Professor Tom Freeman from the University of Edinburgh's Roslin Institute, who led the study, said: "Our approach, which helps us to find out exactly what cells make up a tumor is like deciphering which fruits went into making a smoothie."

"Although more work needs to be done before this could be used to help patients, we believe that this technique is a step towards better understanding of tumors that could help guide patient treatment," said Freeman.

The defined markers for seven immune cell types, collectively named ImSig, and demonstrate how these markers can be used for the quantitative estimation of the immune cell content of tumor and nontumor tissue samples

The utility of ImSig is demonstrated through the stratification of melanoma patients into subgroups of prognostic significance and the identification of immune cells with the use of single-cell RNA-sequencing data derived from tumors. Use of ImSig is facilitated by an R package (ImSig).